During our last session, I had a group of town guards obviously too large for them to handle which I had hoped they would try finding a way around. The guards were looking for them because they were being blamed for the deaths of many caused by an Intellect Devourer. The guards had noticed one of the players and they decided they would run. They said they would head left (we were using a battle map). I told him that if he headed that way, he would reach a wall. Their response to this was telling me that there is no wall that way because I didn't tell them about it earlier. After 5 minutes of trying to tell them that there was in fact a wall there, I gave up and let them leave through that way, skipping the entire encounter. How can I avoid a situation like this in the future?
If you are using a battle map, there is no wall on that map (as OP stated), you did not tell your players there is a wall before it got important, they didn't have any way to know or expect a wall there, then you made a mistake. Admitting you made a mistake is a solid first step in fixing it.
Is there a chance your players would not make decision to go where they went knowing that there is a wall? If yes, then by not telling about that wall you removed some of their agency. They had to make a decision without knowing basic facts. Of course, PC never knows it all, but seeing a wall is something pretty obvious, and not getting in a spot you can't run away from is obvious tactics you made impossible.
To correct this you can (in order from my preferred to least preferred solution):
Move the wall far enough to make sense that they didn't even see it from the point where they were standing.
Remove the wall entirely, fix maps later.
Apologize and allow a little retcon, allowing players to make decisions knowing that there is, in fact, a wall.
Of course as a DM your word is final, but walls out of thin air may make your players go away. This is, simply, no fun.
When your players starts arguing about such things, you should figure out why exactly they are upset, what was no fun for them. You don't have to make them happy with all your decisions, but it is worth keeping open mind.
Options 1. and 2. may be impossible or just too hard in organized play or published adventures, of course. It is very contextual.
How can I avoid a situation like this in the future?
As Molot mentioned, Mistakes are made as DM. In the future, when you face a similar situation I recommend the following:
- If it's crucial that the PCs deals with a particular obstacle or encounter, then "stop and rewind": stop the scene, explain the players that you neglected a particular detail (if the pc are in position to notice it) and rewind the scene and allow the players to re-do this scene with new information.
- If it's not important, allow the players to move forward in the story and build momentum for a new scene. Think of other ways to put presure in the PCs.
The guards had noticed one of the players and they decided they would run.
Did the guard sound the alarm?
Is the town aware of the intruders? the Tavern? the temple?
If the town does not have walls, are there any guards making rounds to prevent intruders?
As a final note, arguing with players is often part of the DM's job. The Players needs to understand that a 100% accurate description is not always possible (and sometimes, when is not accurate, there might be a good reason). They need to learn to trust your judgment as well.
They said they would head left (we were using a battle map). I told him that if he headed that way, he would reach a wall. Their response to this was telling me that there is no wall that way because I didn't tell them about it earlier.
Is it they or him?
If one player is making an issue about it, chances are it's that player's fault.
If the entire group is making an issue about it, it's more likely you did something wrong.
It's not entirely clear from your post, but it sounds like you give them the information that there is in fact a wall there BEFORE they actually have to make an important decision as to which way to go.
If you gave them the information about the wall before any relevant decisions had to be made, definetely leave the wall there.
If the wall is important for any reason, story-wise or any other reason, explain this to your players.
In case you told them about the wall too late, meaning AFTER a relevant decision has been made, just try to work it out with the players.
If the wall is really important to you for ingame reasons, explain this to your players and try to work something out.
If the wall is not important, just remove it ...
I like Mołot's suggestion about moving the wall a bit further, making it impossible for the PC's to have seen it earlier.
There are other options here too, like it could have been dark and the wall could have been camouflaged somehow. Like covered in moss and ivy, ...
Or replace the wall by a moat that is a lot less visible from a distance than a wall.
There are an unlimited amount of creative possibilities here.
Just make sure you are working with your players to create a fun story, not against them.
If they don't want a wall and the wall is not important to you, then there is no wall and no issue?
If they don't want a wall and the wall is important to you, just come up with a cool excuse for why there is a wall or replace the wall with something else they cannot pass through.
There are really two questions here, one in the title and one in the text.
What do I do when a player or players refuse to accept my decisions?
Well, you cannot have a conventional, D&D-type, GM-led game when the player are just rejecting your descriptive and narrative authority. You just can't. You can have some other type of more collaborative game which might also be fun, but it's no longer a conventional D&D game. So I am not inclined, as a GM, to overlook these sorts of things. They almost have to squelched immediately even if the GM is at fault, because that kind of rejection of GM authority works badly (in my experience) with GM-led games-- any time you do something they don't like, this can happen again, with the first instance as precedent. ("What? There can't be a dragon attacking the town, you never said dragons live in this part of the world!")
So I tend to double down, stick to my original descriptions, and if the players want so badly to be in an entirely different game, they can do so. They just can't call me the GM. I am usually not so inflexible on things but, "No, there is no wall there," is a bridge too far for me.
There may or may not be an admission of fault on my part, because I am human and therefore fallible. All GMs are. There may or may not be some discussion about descriptions and error handling and how better to approach things in the future. But unless I'm caught out in flagrant errors (such as, in this case, positively affirming the absence of a wall and then having a wall there) my decisions and descriptions will stand.
How can I avoid situations like this in the future?
Well, that's the rub, isn't it? Generally:
- Describe better. Anticipate better what your players are going to want to know, if possible before they know they will need it, and work that into the descriptions. (That isn't always possible-- sometimes it telegraphs things too much. But probably in this case it would have been possible.) By my lights, you did this to a partial degree-- as soon as you saw they were fleeing as though there were no walls there, you clarified the situation rather than letting them making a total error.
- Empathize with your players. Even when you think they're completely out of their heads, try to see it their way. Because every so often this will happen-- you'll do something you think is perfectly reasonable, justified, even inconsequential, and suddenly not just the one problem guy but all of your players feel wronged. There's not much you can do about the first time, but you can at least note to yourself what set them off and promise to tr not to do it again.
- Figure out as a group how you're going to handle these things in the future. My guidelines are usually heavily weighted toward the GM, unless (a) I've been blatantly and flagrantly self-contradictory, or (b) it's a very long-term misconception that threatens to 'break' a character by invalidating long sequences of their actions over time. But it also comes with a serious promise to listen to their concerns in order to not have this happen in the future.
Bonus Question: Whose Fault Was This, Anyway?
Tough question. I'm inclined to say a little of both. The speed with which you corrected their misconception tells me that you left something out of the description which was obvious to most or all of them, which is not cool. But it also tells me it was not your intent to deceive or sucker them, which would be terrible.
On the other hand, would your players have done something differently (other than heading in that direction) if they had known the wall was there? Maybe, and maybe they could rationalize that they would have done something differently, but it seems highly unlikely to me. This is what I mean above about 'character breaking changes' if it happens on a long time scale.
So you need to describe better, and your players need to roll with things.
The only way through in this situation is to talk things out, determine why there's a disagreement, and reach consensus together.
Sometimes what happened was that you didn't make things clear to the players. When this happens, it's perfectly reasonable to back things up and retcon: "Shoot, you're right, I made it look like there aren't any walls when I drew the map, but in my head there totally are. It's actually an important part of this encounter - without the walls, you can just leave. There's no challenge. Should we rewind a bit to before you started running and try this again, so you can do something different?" Apologizing is fair. This was your mistake, not theirs.
To avoid running into this, it helps to explicitly state the obvious parts of the problem up front when you introduce the situation: "There is a large group of guards ahead of you - too large to fight - and the only side-streets lead to dead alleys. What do you do?" Then, if the players take an action that seems weird to you, like they should realize that what they're doing is a bad idea but it doesn't sound like they do, stop and clarify: "You could go that way, sure, but there's a wall at the end of the alley. You'll likely be trapped. Are you sure you want to?" And remember that you are the players' eyes and ears. They can't perceive anything in the game world that you don't explicitly tell them. So don't hold back! Tell them every detail they might find interesting or useful!
It might also be the case that the players have a good reason to object to what you say. It's not that you didn't explain something properly, it's that you missed something important that makes the detail unreasonable: "That's absurd! We just came from that direction. There can't suddenly be a wall there!" Even if you're the DM, your game still needs to have a coherent fiction.
In this situation, you might have to work with the players and rethink things on the fly to change the circumstances of the encounter so that everyone finds it believable - while still preserving the challenge, of course. "Oh yeah, huh, that is back the way you came. Okay, how about this: There's no wall, but you notice a couple of guards are standing in the way. They must have slipped around as soon as you walked out of the alley. Does that make sense?" "Can we try to run them down?" "Sure, but you'll have to roll for it - and if they manage to block you, you'll have the whole rest of the group on top of you before you can do anything."
Of course, once you understand the reason for their objection, it might still just be the case that you weren't clear enough: "Oh, you're just imagining like a brick wall. No, the wall at the end of the alley is a wall of glowing, golden force. Sorry, I should have made that clearer! Remember how the captain of the guard has rune-patches sewn all over his jacket? He summoned it behind you right as you came out into the street. That's what that noise was."
But it might also be something outside everyone's understanding of the fiction. Maybe your player doesn't understand the terms of the game. Maybe they think you're not playing fair - like you're putting the wall there just to block them from making a decision that isn't the one you want them to make. Maybe they just really aren't in the mood to fight a bunch of guards tonight, and this is their way of trying to avoid it. Maybe something else is going on. The solution is still the same, though: Talk things through, explain why it's important to you to have the walls there, listen to the other person's concerns and be willing to accommodate them, and try to come to an agreement everyone's happy with. Only difference is that if it's a social problem, you might have to do this as a friend talking to a friend, not as a DM talking to a player.