How to stop a player constantly using Detect Magic/Evil?

Question

In a group I play with there is a player who, assuming he has the ability to do so, constantly uses Detect Magic/Evil. There's nothing in the rules against this (that I'm aware of) when it's a class ability/cantrip.

However, it seems to me, from a role-playing perspective, to be extreme paranoia.

If we walk into a new room he casts Detect Magic/Evil, if we meet a new character he casts Detect Magic/Evil, if we sit down to eat at a tavern he casts Detect Magic/Evil etc. And, mostly, it reveals nothing.

What he does with the result afterwards is not really the issue. If we're in a public place, and he hasn't seen them do anything evil, he is unlikely to take immediate action, for example. The problem though is less with what he does afterwards, but with how frustrating it is that he always wants to perform the action at times that seem completely unreasonable — i.e., GM: "You see a barrel." Player: "I use Detect Evil."

If this was just a one-off character, no problem. But he's done it with every single capable character for years. From a GM perspective, I find it somewhat grating when it's impossible to throw in any magic/evil as a surprise when, I would think, a 'reasonable' character would only use either of those abilities when they have a suspicion. I've queried it on him before, and he has explained it's the smart thing to do (he is also a power player).

I am aware of the Undetectable Alignment spell and while this is a great asset for keeping surprises, it doesn't stop the annoyance of him constantly checking every NPC/object anyway.

Should I learn to adjust as the player is technically not doing anything wrong? Or does anyone have a suggestion on how to manage this?

Answer 1

Make the campaign manage this

At low levels the basic method of detecting magic is through the use of the spell detect magic. At low levels the basic method of determining whether a creature's evil is the paladin's spell-like ability detect evil. The spell detect magic has verbal and somatic components and, when it's cast, provokes attacks of opportunity. Using the spell-like ability detect evil also provokes attacks of opportunity. Both require the user to concentrate to maintain them.

In other words, every time the character casts detect magic, he's actually casting a for-reals spell. Right there. Now. Because they lack the skill Spellcraft, most creatures won't know what spell it is while it's being cast. But most campaigns do assume even a commoner has a passing familiarity with magic: they know it exists or know it when they see it. That means, even if the caster explains what he's doing, friendly creatures will be on edge and less friendly creatures will be wary. However, paranoid creatures will dive under tables, and hostile creatures will seize the opportunity to stab the caster in the face. When a dude starts wiggling fingers and chanting nonsense, he can say he's casting detect magic but the spell could be fireball and the only way most find out the truth is to see what happens when the caster finishes casting the spell. For many creatures, that's like hoping a gun fires candy.

A spell-like ability draws less attention, but it still draws enough attention to provoke attacks of opportunity. Folks nearby know the user is doing something, and because there are no obvious outward signs beyond a 3 second or so window during which the user lets his guard down, that's a really important window. Folks will look for that and will at least ask what he's doing, if not punch him in the kidney just to be safe.

I'm of the opinion that a magic-saturated world would be extremely paranoid about folks casting spells (and, in the same vein, using spell-like abilities). One lone spell can destroy the lives of hundreds of people, leave a community devastated, or reshape the very landscape. A caster can tote a dozen WMDs in his noggin and no one would know! Everyone should be on the lookout for casters. Casters should very carefully explain to onlookers what spells they're casting. Towns should have regulations about casting. Towns should monitor casters. No one—not even a paladin—should be able to, for instance, walk into the mayor's office and, without asking or warning, use a spell-like ability in his presence. That'll earn the paladin a pike in the gut because he just tried to use a spell-like ability on the mayor! The mayor and his guards don't, won't, and can't care that it was only a silly little detect evil when it could've just as well been dominate person or earthquake.

This all assumes an adventure in civilization. In a dungeon, this only matters during negotiations but the same guidelines should apply. Unannounced casting or use of spell-like abilities should cause tempers to flare and negotiations to end.

The character is being paranoid. As an adventurer, he's allowed to be. But is the world being paranoid enough about the character?

Not all evil is EVIL and not all magic is MAGIC

In a world where possibly more than 1/3 of living (and not-so-) creatures are evil and magic is everywhere, being able to detect evil and magic isn't really that big of a deal. A few semi-false positives should be all it takes to curb a leap-before-looking attitude of attacking every creature that shows up as evil or robbing every creature that possesses a magic item.

The GM should keep in mind that being evil isn't the same as being villainous just as being good isn't the same as being virtuous. Pedestrian evil should be everywhere: the shopkeeper who sells dented goods at full price, the miller who underpays local farmers for their grain, and the town guard who'll look the other way for a little coin may all be evil. And while most of that won't show up with detect evil, evil often achieves success on the backs of good and neutral, so it should come as no surprise to PCs that many lower- and mid-level townsfolk—despite not eating babies, worshiping Orcus, or kicking dogs—just so happen to be evil.

Also keep in mind that it usually takes a significant evil for detect evil to register any evil. That is, typical evil creatures that aren't outsiders or undead don't show up on detect evil until they've at least 5 Hit Dice or levels. (Creatures with cleric levels and other classes with the extraordinary ability aura show up earlier than that, though.) But Pathfinder—for good or ill—doesn't provide the same grainy distribution of alignment, levels, and classes that its antecedent D&D 3.5 does. That leaves the GM free to populate towns with as many level-5-or-higher NPCs as the GM desires and make those NPCs evil if the GM wants.

Like making evil more common, I also recommend making magic more common. Even a level 1 commoner's budget can reasonably include a magic item or two. (They prefer potions, but as tzxAzrael recommends, a few very-low-powered custom magic items are great for challenging players' expectations.) Consider also the tendency of folks to have gotten the spell magic aura cast on their stuff—despite its saving throw and duration of days, it's really inexpensive—, whether so they can appear more important or less. (I can imagine a ritzy party where folks paid to have magic aura cast on everything so the place lights up like Warehouse 13 when detect magic is used… just to show off.) Further, longstanding architecture should incorporate a magical convenience or two, perhaps so much that it permeates the grounds. (In campaigns I run, for example, the spell hallow is frequently a feature of important—and sometimes unimportant—buildings and areas. As an aside, secure areas—or areas that were used as secure areas until they changed hands—often incorporate thin sheets of lead to foil the vast majority of detect spells.)

Knowing that there's evil or magic afoot shouldn't destroy any plots if PCs must first determine which evil or magic is really important.

Answer 2

Considering there is a casting time and a bunch of cues that he's doing this, how is the world reacting to his constant spellcasting? It seems that the real solution is there.

Do his fellow players stop to wait for his results? When entering a room, in the time it takes for him to cast Detect Magic and Detect Evil, the other players will most likely have already explored most of it. (Unless they agree it's sensible to cast the spells, in which case there's no issue).

In addition, whoever is in the room is likely to have an opinion of the character pretty quickly, and it won't be a good one.

Imagine, if you will, that one of your friends, whenever he enters a room, stops just before he crosses the doorstep, leers suspiciously into the room for a few seconds, then pulls out his smartphone and uses it to scan the room for a few seconds more while talking loudly into it. Imagine the reaction he would get from people watching this.

At the very least, he is going to have the attention of everyone in the room, and at best they'll be amused at the crazy guy. In the more likely scenario, they're going to be annoyed and at least one person will tell him they don't appreciate being scanned like that. If it's a public place, the owner might tell them to not do that again and/or for him to get out.

Now, to make matters worse, imagine he does this when it's common knowledge that in addition to taking pictures, smartphones can project cones of fire and ice or even subtly mind-control others and that there's no real way for a commoner to tell what's about to happen.

There's a reasonable chance that unprovoked, sudden spellcasting by an unknown character has people ducking under tables. If there's any important officials involved, the player will almost certainly be tackled by a bodyguard and charged with something. He will probably be under review by the local advisor to see what he did/tried to do. If there's any city guard involved, at best he'll be shouted down. If the guards are equally paranoid, they might also tackle him and lock him up.

Keep in mind that "I cast Detect Evil and Detect Magic" might be a brief sentence, but it involves at least 12 seconds of pig latin, waving your hands, standing still, and gazing around a room, in a world where it is known that talking pig latin, waving your hands and gazing around a room can do anything from "nothing" to "the entire room is now on fire". Your character will be perceived as a paranoid crazy person in the best of cases, but if he is a stranger, he is most likely going to be met with suspicion or agression.

Answer 3

The root of this issue is framing, and a disconnect between your players assumption of the world and the world you want to run. If your group is aiming for any sort of immersiveness and not just a hack and slash dungeon crawl, your player is not playing "smart" at all. The first thing I would suggest you do, is sit down and make sure you're on the same page as to what you want from the group. If he's a power gamer, it's unlikely that he'll want to change his playstyle, but he may decide to be more cooperative in the future.

If you're on the same page as to what you want from the game, then try to make him see that it actually isn't logical or "smart" to do what he's doing. Good GMing usually starts with "yes, but..." Here are some reasons why it's not logical:

• Detect Magic and Detect Evil are spells that have verbal and somatic components. This means that in order to cast them, there will have to be chanting and hand waving going on. Metamagic feats that remove these components are a non-issue because then it is no longer a cantrip and becomes a limited resource. There are a million reasons why obviously casting a spell everywhere you go is not logical: it could be seen as a threatening action, it could out you as a magic user, it could earn you a bad reputation, it could offend somebody important... the list goes on.
• If he's just using this ability at the start of every scene, then he's actually just using meta-game information that the scene has started and there's probably something important here, but his character doesn't actually have a reason to be casting magic. If he wants to cast it all the time everywhere so that he has an in-game reason to do so at the start of a new scene, remind him that it will take him 4 rounds minimum to scan a 360 degree circle around him. So, severely hamper any travel times. (he's basically asking you to take 20 on his Detect Magic check, and your answer should be yes, but...) In essence, his character wouldn't actually be doing any of this as it would be a terrible bore, waste of energy, and waste of time. Though because the player is removed from the boredom and drudgery, he incorrectly assumes its a logical thing to do. You might be able to prove your point by demanding that he has to explicitly say every time he wants to use detect magic. It gets annoying to everyone real quick.

Paladins receive Detect Evil as a spell-like ability, which means no spell components. All one needs to do is concentrate. This still doesn't become a big problem due to the fact that Detect Evil really doesn't give you any useful information. Unless you are a cleric, undead, or outsider, you don't give off an evil aura until 5 hit dice. That means that mostly everybody in a realistic medieval world is not even going to show on Detect Evil even if they're a serial killer. Also, just because someone is revealed to be evil-aligned, does not mean that they have intentions of performing evil actions, or have broken any laws. A Paladin using this ability would not be ethically able to strike justice against someone just for coming up as evil-aligned (though it might be logical to keep an eye on them).

Try to be a little more reactive with the world around him and with a little creative GMing he should quickly see why it's not logical. This could easily lead to an argument over "what's logical", but in all honesty this player sounds like a real problem anyway and as I said, that should be the first thing to be addressed. Just remember to keep balance in mind when dropping the GM hammer. If you can, answer "yes, but..." instead of an outright "no." These are his characters abilities after all, and he is (supposedly) a hero.

Answer 4

Gaming for Optimization

The motivation behind casting a free spell a lot is that you get the benefit with little cost. This thinking appeals to the type of player who enjoys optimizing for maximum "advantage": anything from gold to xp to anything that is a stand-in for "winning" in an rpg. It is important to understand this about the player. It is also important to realize it is valid: it is fun to run a character "the best".

Gaming for Narrative

It is also important to understand you're deriving your fun from a different source, which is being impacted by the same trick being used over and over. You find fun in the story, and this very mechanical and repeated action runs counter to a story.

Reconciliation

As a GM you have the hard problem of reconciling these two desires. How you respond will, ideally, feed both of you and you'll both find it fun.

Quashing

You can attempt to quash the behavior. There are lots of ways to go about this: a fiat rule that the spell can't be used, having it never return a result or return only hostile results. The danger here is that only one of you is served in the best case and often neither of you will be. The player is not going to stop casting the spell no matter how many times it does nothing because eventually, it might. So it's just taking up your time. Fiat rules are draconian and having all NPCs be immediately hostile is both narratively damaging and means there are a lot of juicy opportunities for the optimizer to cash in on other rewards through combat.

Shorthanding

Given that it's a common action you can just shorthand it: have a red or green card available and just flash it when there is a result. Let the player know that is how you'll communicate it so you don't spend game time going through the rote motions. You can probably ameliorate most of the damage through a similar trick.

Adapting

The harder but more rewarding path is to have fun with it: given that this behavior is part of the character roll with it. Imagine someone doing a similar "checking behind the curtains" in the real world. Such a "Dwight Shrute" person will elicit a range of interactions.

Scorn is a common one, where the person doing the uncomfortable thing is mocked for being weird. He's made to sit at the "loser Mage" table in the tavern. Bouncers check his ID twice while letting everyone else in. Barkeeps fill his beer only half way ("If you're casting spells so readily let's not get sloppy, ok?"). Lords will refuse to speak to him because he's clearly too low status because he's acting weird. Employers will pay less because it makes the group seem amateur. Bigger mages will offhandedly remark how they stopped using such ridiculous spells years ago.

Humor

Some characters will take advantage to get their kicks. The tavern jokester will ask him to repeatedly cast it on everyone in the room. ("Are you sure Fred isn't magic? Have you smelled him? Check again!"). Others will ape him, using the behavior as the basis for a bad impression. The Lady of the manor will ask him if he can do anything, you know, more showy. People will use it as a hook to lure him into seeming even more ridiculous. An attack of opportunity might be a pratfall right into the Mage.

Honest Bait

The habit has upsides: some characters might see it useful to have someone weird go in ahead and scout things out. This validates the character choice while being an adventure hook.

It can be a validating moment if after many useless attempts a character sincerely thanks the Mage for having the foresight to cast detect evil and saving their life.

Weird People Group

If the character is weird he will attract weirdos. Come up with a character who casts an equally weird spell and have him try desperately to be the mages friend. You can inject levity and hijinks while underscoring and circling the strange behavior. Have another character talk to the Mage about how they're worried they're developing a bit of a reputation that will hurt their career, in very emo, over the top way. ("Egon, I'm not sure carrying that proton pack everywhere is helping your dating prospects...")

Conclusion

Try and understand what the player finds fun about the behavior and affirm it: you want them to have fun. But affirm it in a way you also have fun and serves the story. Use the behavior to hook in things you already want to do. If you're successful at this the behavior will become less a thing used for mechanical advantage and more a thing used to as a consistent "beat" in the story rhythm.

A final note: the Bartle Taxonomy of Player Types can be very useful for understanding where the player is coming from, and where you are coming from, and gearing interactions to satisfy both. Avoid writing them off as a "power gamer" or "rules lawyer".

Answer 5

To draw an analogy, I'm short-sighted and I wear glasses. All the time. I don't just put them on when there's something I want to look at. I wouldn't appreciate someone telling me "look here, this ability you have of seeing things at a distance is rather disruptive, wouldn't you mind using it only when you absolutely have to?". And, if I was a character in a role-playing game, I would not expect to have to continually tell the GM, "I look at it through my glasses. I look at it through my glasses. I look at it. Through. My. Glasses. Just. Like. Always".

Your guy has a useful ability that he can use all the time at no cost. Except when he cannot cast for some reason, it might as well be passive. There are social consequences to spell-casting which you've chosen not to make bite in your game world. These range from people being offended that he's testing them, up to people in bars jumping on him and tying him up. They don't know what he's casting, but they know to take out the magic user first. So, you're not doing that, and he has the ability to detect magic/evil all the time. Also, he's always muttering to himself, which sometimes puts a damper on conversation when he stops talking for a moment to re-cast. These things won't change unless he says otherwise.

Either make the consequences bite, so that he has to choose whether or not to spellcast, or just let it be assumed that he's casting it all the time, and tell him when he gets a hit.

There is a middle way, which is to somehow physrep the spell. Simulate that although the cost of casting it is zero in rules terms, that's because a single use is negligible rather than because it's literally zero. You could for example give him a little flag. When he holds the flag up in one hand then his detect is on. If he puts it down (even for OOC reasons such as eating or rolling dice), well, I guess his character was distracted from casting. This isn't properly realistic, so you could instead give him an actual incantation to recite in character, and an egg-timer to approximate the duration (of course you're not always in real-time, but when you are it works). It might make the point that his character is, in effect, continually doing pushups and taking advantage of a rule that one pushup is trivial. Whether a power player will take any notice of that point, or just cry foul that you're introducing house rules to nerf him, is a matter of diplomacy ;-)

Answer 6

Honestly if I had magic powers without limit I'd be using them all the time.

Perhaps he's wasting game-time and breaking the immersion so just tell him that you assume he's always casting and will let him know of any evil when he enters the room.

This isn't really ruining the game, it's how it should be played. Just like a thief should check for traps everywhere. If you can't sneak a demon into the party's midst, great! There are still millions of other tricks he won't detect.

Now it might cause looks and delays possibly unwanted attention so you might suggest the option to turn it off until further notice (Although I'd argue that after using it so much the character probably finds it second nature and doesn't even notice he's doing it, perhaps he gets to the point where he can't turn it off).

One of the better DM's I've worked with always made it his goal to mold the game around his players. You don't want to try to force the characters to follow some module as though it was a computer game with all the possible tactics either predicted or disallowed.

Doesn't mean you can't have fun with it though--you're the DM. Maybe he can't shut it off and evil creatures give him a headache... maybe he starts seeing things... Just meaningless ghosts that try to talk to and distract him because of his over sensitivity.. lots of fun to be had.

I suggest you let the players do what they want and find ways to make it interesting.

Answer 7

I like the idea of a character using detect magic all the time. He or she walks in a world that the mundanes don't even know exists.

Detect evil, on the other hand, isn't as useful as the player might think.

So, the character detects the captain of the guard as evil. Now what? If they attack the captain, the rest of the guard attack the party and either capture or kill the character. "He detected evil on my spell" is not any sort of defence for attacking a member of the city watch.

It is useful to the GM however, to set up paranoia. That character now knows the guard captain is evil but no-one else does. Other people tell them they are mistaken or lying. No-one believes them, so they have to work against the captain in secret.

Answer 8

It used to be so that detect magic would give off a visual signal such as blue glowing eyes, and I assume the others like detect evil would have had a similar tell.

For the detect magic there are are a few things you could do.

• Have the items hidden within an extra-dimensional area such as a bag of holding.
• Be under the effect of the spell which hides magic auras by the name of magic aura.
• Have the NPC carrying the items in a lead box or lead lined bag.
• Have someone else carrying their magic items who returns them after they are scanned.

Detect evil is a bit more complicated. You've already mentioned the most likely aspect. So consider the environment instead. Unless they still and silent the spell, it's very obvious that they have cast it.

• So make it against the rules of the tavern or town.
• Go the route of a false positive, either in the way of someone who is inherently evil but has not yet done anything (say an evil cleric who deals with final rites), or someone who is under a curse and the curse makes them appear as evil.
• You could also have someone who is lawful evil, so let them find the captain of the town guard who is lawful evil.
• Let them cast detect evil on a paladin or CG barbarian who takes offense to this for demeaning their honor.

Finally, have you talked to the player about the way you feel they are abusing this? Yes it is a "smart thing to do", but the game is meant to be fun.

Answer 9

Everybody already mentioned the fact these spells are not instant to cast and some people can take that badly. I agree with them but will try to suggest some other solutions.

First, you can by GM fiat simply decide that these abilities are not at-will anymore. Make a houserule which says "lvl 0 spell slots are limited to 40 uses a day", it won't break the game mechanics but will make your player think twice. Concerning the paladin's detect evil, you can apply the same nerf or decide that the god will get upset if he keeps asking for scan when it is useless.

Secondly, you can set an example of bad consequences for using these spells. For example there can be a trap in a dungeon that activates when someone casts a spell in the room. No need to repeat that ad nauseam, just place one example to set the fact that "this can have consequences".

Finally, keep in mind the weaknesses of these spells:

• Detect magic doesn't detect hidden magical objects, it's really more a way to identify something. If it's some kind of trap or puzzle, you can bet the guy who set it hid it so you cannot just Detect Magic it.

• Detect evil doesn't work on filthy peasants. For it to work you need to have an evil aura, which means you are an evil priest/antipaladin or a high-level evil character. There is no real point casting it each time you enter a room as most of the time it will simply do nothing

Answer 10

Take advantage of the inherent limitations in the spell. Other answers have already touched on the casting time, so I'll skip that one, but there are a few others to exploit.

• Non-detection of low-level evil
  An evil creature of 4 or fewer HD does not give off an evil aura, unless it's an Outsider or Undead, or is a Cleric or Paladin of an evil deity. So you can fill up a tavern with 4th-level evil rogues, fighters, and wizards, and none of them will give off an aura. When the character (openly) casts Detect Evil and confidently declares to his allies, "We're good, guys; nobody here is evil," the entire tavern ambushes them, knocks them unconscious, steals all of their stuff, and sells them into slavery.

• Gradual "honing-in"
  Upon studying a given area while concentrating on the spell, after the first round, the only thing that's revealed is a simple Yes/No - is there some evil around, or isn't there? To learn more, the character must maintain concentration on the same area. In the second round, they still won't have all of the possible information, they'll only learn two things - the number of auras in the area, and the strength of the strongest one. It's not until the third round that the strengths of all of the other auras, and their specific locations, are revealed. So you can put the players in front of one evil 10th-level Cleric, who happens to have exactly 5 evil-aligned magical items in her possession that give off faint auras, and also has 5 good-aligned hostages that are bound, gagged, and have had illusions cast on them to make them look like Undead. When the PCs attack, the illusion is revealed, and they must face the moral dilemma of having injured (or possibly killed) the innocent hostages. (Yes, like that scene in Dark Knight.)

• Out of your depth
  If the caster of Detect Evil is good-aligned, and the strongest aura's source is sufficiently more powerful than the caster, they can become stunned after the second round of concentration. I don't think I really need to give an example for this one. :)

When the player realizes that the spell isn't a form of True Sight†, and that there can even be consequences for using it at the wrong time, they should begin to be a little less reliant on it.

†_{Warning: TVTropes link}

Answer 11

Ages ago I read interesting article about this issue. Author suggest that, casting those spells and it's effects will be noticeable for most people around caster. And some low born folks might have some prejudice against spell casters. Hence, player instead being conned by greedy shopkeeper, will end up in prison accused for witchery.

By addition, If you look at definition of good and evil character, you will realize world is actually full of evil people. Innkeeper who is driven by greed, who mixed ale with water to sell more. Farmer who mistreat his employees. Nobleman who's wife was killed by bandit, can also become evil, if revenge became main purpose of his life. Cleric who serves lawful good god could also walk on evil path, committing bad deeds and justifying them with greater good. So sometimes result of Detect Evil spell could be really supprising.

Answer 12

This should be seen as a storytelling opportunity, you may not realise all the times a GM is internally screaming "just use Detect Magic you idiot! This is a game all about magic items and you won't use the one thing to detect them!".

This problem actually a solution to the other problem: how are the Player Characters going to be special in this world? How are they going to do things of significance that had never been done before. Like how do you have your party find The One Ring that has otherwise been missed by everyone else who ever came through here? Because they used detect magic.

You need to harness Detect Magic as the beacon to drive the story forward, work with what you've got. Allow detect-magic to be a vital element in scavenger hunts like looking for magical macguffins.

If is actually still possible to throw in magical surprises:

1. If it is not within the 60ft cone they won't find it before it comes into play
2. many effects (such as Rope Trick) are explicitly immune to divination spells so you can hide things from Detect Magic.
3. Magical auras are easily suppressed such as by Magic Aura or the other limitations such as the inability to penetrate more than 3ft of earth or thin layer of lead.

You can't really say it's "unreasonable" for him to use such a flexible spell, he has actually very good reason to use Detect Magic as magical auras are important it's good to detect them.

You should let them detect them, you should empower them with their decision making and join in the party on the adventure, have fun with it like have a magical aura be detected inside a tree that a knowledge nature or survival check reveals is as old as an ancient battle. The Fighter hacking into the body of the tree you find the Magical Talisman of world changing importance that the tree actually grew around.

It's not like the Bestiaries and rules books aren't already filled with examples of threats that don't have their surprise particularly ruined by Detect Magic. Using Detect Magic on a barrel shouldn't tell you everything, it may have a goblin inside. It may or may not have gold inside. Simply scanning with detect magic will only give you a clue, it's worth throwing it everywhere as it might reveal something like a rogue is hiding inside totally decked out in magical gear.

Answer 13

Instead of making the whole world start to turn against him and his spells, have you considered just asking the player to try and cast Detect spells only when he suspects something?

"Hey, I'd like to suprise you guys or have things be a bit mysterious, and you're making it hard with those spells, could you tone them down a bit to give me the leeway to make the game more interesting?"

You know, talk to him as a person.

Answer 14

All the answers so far are exceptionally detailed, but I think the general takeaway is more important - you effectively have two choices:

1. Speak with the player and explain why letting monsters eat you is a good thing for fun (realism and the fact interesting stories rarely occur when everything goes right).

2. Shoot the player in the kneecap with an arrow (metaphorically speaking - disable or limit their ability/desire to use the power).

Option 1 is self-explanatory and most likely the preferred option. Depending on the relationship, I might even explain why I personally found the behavior frustrating. Even if you have spoken with the player before, that isn't always the same thing as clearing up a situation in my experience.

That said, it sounds like Option 2 is your best bet.

I am aware of the Undetectable Alignment spell and while this is a great asset for keeping surprises, it doesn't stop the annoyance of him constantly checking every NPC/object anyway.

Then you must give him a reason not to. He sees using the ability as a bottomless advantage. You must alter this perception if you can.

Altering the rules is not a good option, I believe, since this is obviously a one-sided unrecoverable disadvantage and may come back to bite you in other ways (e.g having your house rule used against you somehow). Having him suffer an in-game "curse" of some sort (outside the complexity of casting and NPC hostility) would be my preferred method.

Curse You...!

As mentioned elsewhere, this could be as simple as a limit on daily usage or more serious (but creative) effects. The upside is that, depending on the effect and reasons behind it, this could offer expanded opportunities for role-playing.

"Curses" don't need to be directly magical in nature, either -- besides divine blessings (or taking away of that favor), the character could suffer a physical "curse" as well. Perhaps that sprained pinky never healed right and now there is a %50 chance the character is really casting "Detect Good" (for "Detect Magic" this could just be a failure to detect an aura properly).

Also, since you mentioned you felt this might be a symptom of character paranoia, perhaps the paranoia is real and the sufferer becomes "worse" when certain abilities are used to "feed" it. This could be anything from false positives (everyone is evil and every item is magical) to actual hallucinations (that guy has a concealed crossbow!).

The drawback of cursing a character is that the player may still feel singled-out and upset at this treatment. Because of this, "beneficial curses" might be a better option. Essentially, you offer the player a benefit for reducing his usage of a particular ability.

While the benefit of course doesn't necessarily have to be related to the suppressed ability, since he REALLY likes to detect things, perhaps NOT detecting things for X hours/days would yield a significant advantage to him (he can detect things that are normally undetectable, etc.). For extreme cases, the ability could be disabled/removed temporarily or permanently. Magic reduction or suppression could come with advantageous items as well.

Of course, any "curse" would need to be selected carefully (to avoid hurt feeling and so other portions of the game don't unravel) but this option also opens up story line possibilities as well.

...And Your Damnable "Detection"!

From a GM perspective, I find it somewhat grating when it's impossible to throw in any magic/evil as a surprise[...] Should I learn to adjust as the player is technically not doing anything wrong[?]

I believe the answer is yes, in a couple ways.

First, abilities are there to benefit the player. So at the heart of it, there SHOULD be situations where powerful magic or evil can be discovered and earns an advantage.

Secondly, it sounds like there is a note of infallibility about the detection.

Having cursed lands where everything is essentially evil (or simply doesn't work the way one normally expects) are valid options. But also remember not all NPCs/creatures who might take adverse actions against the PCs are themselves evil (they may be puppets or simply misguided).

Likewise, "evil" is an acquired state in many cases -- corrupting influences (magical or emotional) often take time to accrue before a creature is truly "evil" as a distinct trait. That doesn't prevent actions which others might perceive as evil along that path.

On the mechanical side, remember that spells and spell-like abilities (minus V/S/M and some casting time disparities) are subject to suppression or negation, at least for areas (and frankly any evil NPC worth her salt will likely take some pains to conceal the fact they have an evil aura).

Supernatural abilities don't function in anti-magic areas. Likewise, other magic or deliberate suppression might make detection impossible or flawed for magic auras.

There also may be other hindrances. For example, despite being at will, paladins can only concentrate on one person or object at a time. Depending on selection and situation, this could be a real disadvantage.

The bottom line, in my opinion, is that not detecting something doesn't mean it isn't there (and thus potentially allows for "surprises").

Answer 15

Duration based on RAW for these abilities -

Detect Evil - Concentration, up to 10 min/lvl

Detect Magic - Concentration, up to 1 min/lvl

Each of these spells takes up to 3 rounds of active concentration (at 6 sec/rnd) to get full effect (+1 or more rounds to cast).

If the party wants to spend half a minute waiting on a character before entering a building, let them do so. Maybe they also happen to acquire a reputation for this in town? It might even be about them being cowards.

You (seem to) indicate that this PC is using these abilities based on a class feature rather than a spell. The 'concentration checks' section of the Pathfinder SRD seems rather vague on what constitutes a 'distraction' so - in cases where this is a class ability - maybe the concentration check DC increases based on the amount of time you've spent trying to concentrate recently, with a failed check adding to that significantly if not removing your ability to focus on using that class feature for a set amount of time (maybe until the next rest?). If PCs complain, you could liken it to a 'class feature' being a process that uses your internal computing (brain?) to determine things while a cleric/mage is using an external computing power (a magic formula powered by mana or something) to send results directly back. (local processing vs. an OLAP cube? Maybe?)

TL;DR - punish the overuse of class abilities with stacking concentration check penalties that reset on 8 hr rest periods. Penalties on the use of mage/cleric spells are not necessary since they're already expending a resource.

Answer 16

Could you consider "polluting" portions of the world with a low-grade dweomer? This way you could selectively degrade the utility of 'Detect Magic' in the situations of your choice. You might work in a legend that it was put in place to partially negate the advantage of powerful milieu- or story-specific antagonists which had the permanent ability to Detect Magic.

I'm not sure how this would work for evil, though.

Answer 17

In Piers Anthony's Blue Adept, the protagonist became casual about spellcasting until he tried to use magic in a room full of amulets that were triggered by magic. Even one such amulet that releases (for example) a demon when a spell is cast onto it would wreck your character's day (in-world, at least; in-game it could be amusing for everyone involved).

Answer 18

Both detection spells are magic based. Make the trigger for traps magic based. They go off if magic is used, or just particular spells (detection spells). Make the person learn to play their character without a crutch. Or, if they use the crutch, a barrel explodes by another character seriously injuring them. Or make the explosion temporarily injure their ability to "see," so they can't "detect."

Answer 19

Require specific motions (eg peering closely with fingers parted over eye) as a requirement of the spell, and a moderately long delay (eg 3 minutes) which would be awkward to do continually.....

Then make a social stigma of people who continually do so as it would be both social awkward, and extreme personal insult to strangers, and a social faux pas to show such invasion of privacy and mistrust to others.

As for dungeoneering: extreme paranoia is appropriate! Not everything dangerous is evil (traps etc are often good, as they protect against theft and worse dangers (eg nasty/dangerous artifacts)). Some areas are also frequented by evil or good people, optionally leaving everything in the location with the hue, so only exceptional examples would show up.

As for the bad guy sneaking through the village in disguise. The disguise will have to use a blocker against such magics (perhaps a common "cantrip" token will be available in the marketplace to protect privacy if people with "privacy invasion" powers are not uncommon - eg "a common working peasant hedge magic pultice/ring/necklace/mojobag that protects from spying and eavesdroppers, but only very low levels, that happens to mask against the detect spell at low levels. There is warning to the PC if they notice the protection (easy) but common use against privacy invasion will make the item less of a giveaway - without nerfing the spell completely.

Also often evil people will hide behind a veneer of public good - so spotting an evil aura might just be the mayor's personal ambitions on someone who otherwise does excellent community work (eg set up schools and orphanages) but for their own advancement.
While others might seem good (entirely in service to dark powers and masters) yet never hurt, lie, or sacrifice things - but daily serve to advance dark causes.