How do you handle when the character is not aware of something that, per game mechanic, the player has to be?
The classic situation is the typical Perception roll, where simply asking for the roll reveals to the player that something may be up. Some GMs make the roll themselves or use a log of pre-game player generated rolls to handle such situations but there are others.
How about an NPC using Bluff and the character failing to Sense Motive? Obviously the character is fooled but the player will no doubt be skeptical. Can you declare "You are convinced that what the man says is true and will have to respond accordingly" and really expect a player to follow along, even if detrimental to the group. "Sure, we will, go ahead and walk in the dark room, I mean, the guy said it was ok and all."
How about disease or poison saves that dont show symptoms for some time? Knowing they failed and were exposed will obviously affect decisions afterward when in reality the character would assume they were fine most likely given a lack of immediate affects.
Im sure there are many many others but this makes the point. How do you handle such situations?
Players who have fun playing along with botched rolls will do so even though they know OOC they failed IC. Players who don't have fun with that won't and should not be forced to do so.
My two cents.
I run perception as an always-on thing. I have them roll at given intervals when traveling, entering new areas, etc, even when there is nothing there. For poison and disease, if a player is exposed, I mark it down and have them make the save when the symptoms would actually appear, on a pass, nothing happens, on a fail, they do appear.
Yes, the occasional false roll is a good idea, Ive used that one just to keep things tense, if nothing else. The exposure idea is a good one, consider it borrowed!
Players who have fun playing along with botched rolls will do so even though they know OOC they failed IC. Players who don't have fun with that won't and should not be forced to do so.
My two cents.
They don't have to have fun with it, but by no means should the GM allow them to alter the course of events or act on metagame information.
If someone has to be a party pooper and refuse to roleplay what is a definite roleplay situation (being conned, not noticing something), then they need to sit out quietly until they can get with the game.
It's called "Separating Character Knowledge from Player Knowledge" and it's part of being a good Role Player. Experienced Role Players can compartmentalize, not acting in character on Player Knowledge, with some effort.
If your players are having difficulty compartmentalizing, there's a few things you can do.
1) Make Secret Rolls. If you don't think a player can avoid acting on player knowledge, roll in secret so the players don't know the roll has occurred. Alternately, you can have the players make common rolls, like perception, for no reason. That way aplayer won't know wheter there's actually any thing to spot.
2)Avoid Meeting Player Expectations. If a player expects an NPC to lie, have him tell the truth instead. Better yet, have the truth be something the players will expect to be a lie. "It's totally safe to enter that dark, foreboding room, I promise."
Explain to the players that the only way you have to convey the believability of an NPC is via Sense Motive. If the players ignore that, they're going to waste a lot of time and miss a lot of XP and loot by mistrusting everything anyone says.