Nothing kills the mood like accidental metagaming.
Most GMs are well acquainted with how much metagaming can damage a campaign when players intentionally seek to circumvent the rules because they feel limitations are a total buzzkill, even when they’re applied fairly. It’s a more subtle problem when your players accidentally metagame because a requirement of the rules gives them knowledge out-of-character that their in-character selves will lack.
One of the clearer examples is when it comes to perception checks. Spot, Sense Motive, Notice, Alertness, whatever the name for it, the conundrum remains: asking for a roll at all can give the players knowledge that there’s something to notice, even if the result of the roll for their characters leaves them otherwise unaware.
Say an evil nature spirit is stalking the party through an otherwise peaceful forest at night, hoping to strike with her sneaky woodland vengeance and steal their smelly city-things for her own (because who doesn’t want smelly city-things, amirite?)
The GM rolls the sneaky spirit’s stealth check and asks the party for their relevant perception checks to see if they manage to spot the lurking little nymph skulking through the underbrush nearby. Because the nature spirit is good at stealth and in her home turf at night, none of the PCs spot or hear her skulking about.
At that point, the PCs would typically continue on through the otherwise peaceful forest until they grew tired and needed rest, and would then bunk down for the night, cautious only of the typical worries within a forest, like bears eating their trail rations or dire chiggers getting into their underthings.
Problem: while the characters are unaware, your players were just asked to make a check to notice things in the Otherwise Peaceful Forest (TM). If you tell them “you don’t spot anything out of the ordinary,” most players will assume they failed the check, which implies that there absolutely is something out of the ordinary out there and that it’s capable enough to elude them, which would make anyone worried before setting up camp that night.
Suddenly they’ll be discussing posting a three-part watch rotation with area spells to warn if any unfamiliar feet should tread upon their hallowed camping ground and pillage their supply of treasured +1 s’mores. Players will even defend the choices as “just common sense when camping in the woods at night.”
While that may be true, the actual cause often still lies in the red flag that was the dice roll you called for. Whether your players intend it or not, the mood can quickly shift from a dull, worry-free walk in the woods to the sort of tense paranoia that normally accompanies conspiracy theorists and those visiting family over the holidays.
So how do you help players keep their actions genuine while still giving them a chance to legitimately notice something they legitimately have a chance to notice?
Many GMs who here decide that, for the preservation of the mood, they will evoke Rule Zero to say that, because the spirit is sneaky and on its home turf, the chance of the PCs spotting it is so low that they needn’t bother rolling.
The trouble with that philosophy is that when the players learn that they were robbed in their sleep, they will want to know why, and they’re right to demand it. You’ve removed player agency – that has the effect of making the players seem superfluous and unnecessary, if you can just decide the outcome without their input.
My suggestion: don’t do that.
Instead, find ways to let them roll without letting them know what they’re rolling for. There are a number of ways to sneak a roll into the mix without setting off any warning signs. Half the time, it comes from changing when the roll is made. The other half is providing enough chaff so that a failed check still sounds like a success, which lets it be resolved in the players’ minds.
For sneaking in the roll, I recommend you gather your PC’s stats for the relevant skill (perception, spot, etc) and keep them on a card with your GM notes. Make sure to make adjustments for buffs, penalties or other temporary boosts from feats and items so that the numbers are accurate at the time the perception check is being made. You should be keeping track of buffs and new items anyways, given the number of areas of your game it can impact in a hurry.
Once you have the numbers recorded, you can roll the dice yourself behind the screen when it’s time to try and notice something. Understand that that still leads many players to question the fairness of the roll, because they didn’t make it and they can’t see it. To avoid that, ask your players to roll a die at the start of the session, or even a session or two in advance. Tell them nothing about the roll it’s for or what stats and skills to apply – you have all that already. Record the results on your card. Later, you can let them know what it was for.
The importance here is the timing. If the players roll a die an hour or more before anything related happens in the session that needs it, they’re more likely to forget about it. You’ve given them the chance to roll, so if they wake up naked in the woods, you can tell them why and show them what they already know: the die roll, their relevant skill, etc.
The first time it happens, your players are liable to get a bit twitchy and start jumping at shadows, but the more you do it, the more those fears will dull over time. Do this often enough (even calling for a “dummy” roll occasionally that feeds into nothing at all), and your players will stop trying to guess what the rolls are for. They’ll just play along with what makes sense in character without any out-of-character knowledge getting in the way.
Alternatively, to save on bookkeeping, throw up chaff at the time of the roll to make them think they’ve succeeded, even when they haven’t. Take our nature spirit scenario.
They’re walking through the woods at night. They hear a twig snap. Ask them for the perception rolls. If no one spotted the spirit, they instead see a) a stag that skitters quickly away into the woods, b) the skeleton of a long-dead adventure and his handful of basic supplies, c) a crotchety goblin grandmother setting up her winter home in a hollow in a large tree. The spirit is still out there, unnoticed, but because they spotted something, players will consider the roll resolved and won’t likely give it another thought.
Either way, by shifting up the timing on the roll or baiting the party into thinking it’s resolved itself already, you can keep the mood right for what the characters are sensing without the players themselves putting on their tin foil hats long before they’re due.