I am not sure, I really get it. I’ve read three posts by PensiveandPaper at More Than Dice: post 1, post 2 and post 3. They are about Meta-Gaming. The posts first present the problem, and the other posts suggests how to deal with different kinds meta-gamers. At present there is one post left in the series. But it is not really a problem, that I recognize, which may be due to a different playstyle, so let me give it a shot at “meta-gaming”.
Trolls and fire
This is the classic example,.The adventurer’s encounter a troll, and the players knows that fire must be used in order to proper defeat the troll. May the players use fire to defeat the troll?
Before we start arguing whether or not it is common knowledge in the setting, that trolls must be burned to destroy them, I want to look at the encounter. Is it an important element of the encounter, that the PC’s discover the monsters weakness or not?
As I remember descriptions of trolls from various D&D-creature catalogues, I don’t remember it being an important element in the encounter with the troll, the it is hard to defeat (besides it’s regular stats, they’re usually pretty nasty). Rather it seems to me, that people have heard about or remember their first encounter with a troll and the horror of discovering, that it cannot be defeated without fire. However you can only be told once, that Father Christmas does not exist.
Surprise! The monster is indefeatable
If you want to surprise the players, then pick a new monster or change an existing. That is what the rulebooks recommend, that you do. The huge variety of trolls published for the various incarnations of D&D are great examples of how to change the existing. Or just add a little extra, a troll with Ring of Fire Resistance is a terrible foe for the otherwise well prepared party. In other words no need to stop the players from using their knowledge of the game.
You know it, but you must discover it
Okay, you want that troll-encounter and you want the PC’s to discover the weakness, even though at least one player already knows. In this case, roll dice!
Once one of the players suggest using fire to kill the troll, tell the player that none of the characters are aware of this, and that they must discover this during the combat. With the 4th ed.-rules you can do it as a Skill Challenge (each check would be a minor action or free action performed while fighting the monster). You can even introduce this approach for groups, where none of the player know the weakness, and where their characters are supposed to figure it out (e.g. some of the monsters in 1st – 3rd edition sometimes have the strangest weaknesses, that in some manner makes sense, but are completely impossible for the players to figure out. If they don’t get to read the rulebook, you need to introduce the weakness some other way, it you want the players to employ it). This is much like the ‘Say yes or roll dice’-approach.
Planning no surprises
If it is not an important part of the encounter, then I don’t care about the players talking about a given monsters power. Sometimes I even offer knowledge on succesful skill checks, if the players don’t suggest it themselves. With the average troll encounter, I actually design it with the assumption, that the PC’s have the right knowledge. Surprises are designed as surprises.
Anyone got a suggestion?
If a player’s character is in trouble, it is not uncommon, that I suggest we ask the rest of the group for ideas, and sometimes the players volunteer ideas. The latter is typically done by one of the players asking if he or she may present an idea, I then allow it, and unless the idea seems build on knowledge, that would be seriously out of character, then the player can use it. If it is out of character, the player himself usually mentions this and chooses a different approach.
Meanwhile, somewhere else
The most common situation, where a player needs an idea, is when dealing with NPC’s. It can be important negotiations, tricky intrigues or some other social situation. When it becomes obvious, that the player needs help or time to come up with a clever retort or smart move, I cut the scene. Attention is switched to somewhere else, and the player gets the necessary time to find a proper answer or a clever retort. Then we cut back to the player and continue the conversation.