Should there always be a check (stealth vs perception) before someone can be surprised?

Question

Here are some questionable scenarios:

1. Adventurers go in a cave and clear it out (multiple encounters). On the way out some goblins "Hide" outside the cave with total cover (awaiting for the adventurers to come out and ambush them). Scout leads the way and is surprised.

2. Adventurers come up and see a dead body on the floor (see statues on the sides of the room, see motionless skeletal bodies scattered about the room). The scout approaches and is attacked as the undead/statue seemingly comes to "life".

3. Jack and Jill go up a hill to fetch a pail of water. Jill pulls out a knife and stabs Jack.

What I'm trying to find out with these scenarios is if Surprise should just happen, or if there should be a check of some sort/or no surprise round.

I would like confirmation of my understanding of the rules (the process of the "DM determines who might be surprised" is to do the appropriate checks as needed). Please only use RAW in your answers as I am trying to find only DnD5e answers (not real world or DM interpreted answers - already have a DM, don't need other DM fiat/facts).

Answer 1

No.

See the DMG's section "Using Ability Scores" (p.237) which says, in part:

Only call for a roll if there is a meaningful consequence for failure.

When deciding whether to use a roll, ask yourself two questions:

• Is a task so easy...?
• Is a task so inappropriate or impossible...?

It's simply not true that a stealth vs. perception could never fall into one of the two categories above, so it'd be incorrect to say that the GM must always call for the check.

Answer 2

YES.

According to PHB p. 189:

The DM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other. Otherwise, the DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side. Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.

Thus the process of the DM determining who might be surprised is:

• If neither side is stealthy, they automatically notice each other.
• Otherwise, the DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side.

So I take this to mean there is always a check of some sort.

The scenarios listed still fall under this process:

1. Adventures go in a cave and clear it out (multiple encounters). On the way out some goblins "Hide" outside the cave with total cover (awaiting for the adventurers to come out and ambush them). Scout leads the way and is surprised.

   This scenario should still have a stealth-goblins vs perception-scout check even if the scout didnt say he was actively looking for hidden creatures (use his passive). If you cannot see the hidden creatures, you still have a chance to hear them. This is based off the DMG p.243

Outdoor visibility can be hampered by terrain, weather, and time of day. Creatures can be more likely to hear one another before they see anything. If neither side is being stealthy, creatures automatically notice each other once they are within sight or hearing range of one another. Otherwise, compare the Dexterity (Stealth) check results of the creatures in the group that is hiding with the passive Wisdom (Perception) scores of the other group, as explained in the Player's Handbook.

2. Adventures come up and see a dead body on the floor (see statues on the sides of the room, see motionless skeletal bodies scattered about the room). The scout approaches and is attacked as the undead/statue seemingly comes to "life".

   Here neither party is in stealth and they both notice each other. Despite the creature being motionless, the scout should not be surprised that it attacked. You are already in a dangerous area and are already on high alert (a dead body/skeletons/statues in a cave/dungeon is not normal). Plus the scout was approaching to investigate further. In any case the rule states if neither side is stealthy, they automatically notice each other - thus no surprise. OR, give the scout a perception check to see if he notices something about the creature as he approached/looks at them (failure of the check may mean surprise).

3. Jack and Jill go up a hill to fetch a pail of water. Jill pulls out a knife and stabs Jack.

   In the real world, Jack would be surprised that his friend stabbed him. However this is DnD, neither side is stealthy, they automatically notice each other - thus no surprise. Or there could be a check to see if Jack notices Jill pulling out a dagger and lunging at him with it (failure to notice/act quickly enough may give Jill a surprise round).

Surprise should not just happen, there should be a check of some sort or there is no surprise round. When the "DM determines who might be surprised" he is doing the appropriate/required checks (passive or active) for each of the parties and letting everyone know if there is a surprise round and who can act.

Answer 3

No

PHB p. 189:

The DM determines who might be surprised.

The paragraph then goes on to describe one way that the DM might do that; awesome DM's (and other players) are enabled by the rules, not limited by them.

My examples

1. Terry the Terrific, a powerful wizard is carrying on a clandestine affair with Sandy the noble behind the back of Sandy's spouse Pat. Pat is suspicious and has decided to wait in Sandy's room in the hopes of confronting Sandy's paramour. Now, Pat does not know that Terry customarily enters Sandy's chamber by teleport. Even though Terry was not trying to be stealthy, boy, is Pat surprised! Terry was a little worried about Pat so has been half expecting this and is not surprised. Before Pat can recover, Terry is out of there!

2. Having avoided a terminal conversation with Pat, Terry is recovering with a quiet ale or two. Unfortunately Terry was recognized and Pat has engaged the services of the half-orc thug Alexis to teach Terry a painful lesson. Alexis is not one for creeping around but does know the value of surprise and, rather than calling Terry out, Alexis has decide to walk casually to the bar and suddenly thump Terry in the back of the head. The DM calls for a Charisma (Deception) check opposed by a Wisdom (Insight) check to determine if Terry is surprised. Despite the ale, Terry notices Alexis' intent and bolts out the back door.

Your examples

1. The goblins are hiding, why do you thing Dexterity (Stealth) is not being used? Total cover may give them advantage but they still stink like goblins, need to breath and may lack the discipline to keep quiet.
2. This is analogous to my second example, Charisma (Deception) check opposed by a Wisdom (Insight) is more appropriate than Dexterity (Stealth) vs Wisdom (Perception).
3. Ditto