I’ve seen it a thousand times. Two PCs are facing a problem and some variation of the following exchange occurs:

GM (looking at Player 1): What do you do?

Player 1: I’m going to do X.

Player 2 (glancing at Player 1’s character sheet): X? Are you kidding. You have Y, why wouldn’t you use that?

Player 1: Fine, I’ll use Y then.

This is a classic example of a player using OPC (other player’s character (sheet)). Sometimes, OPC is used to help teach a newbie the ropes (“Did you know that your character can do X?”). On the other end of the scale, there are players that use OPC to further their own ends or ensure optimal play at the expense of discretionary play.

For example, I’ve seen OPC at a table where experience is not a factor. For whatever reason a player has not shared all of her abilities with the rest of the group, yet Player 2 scans her sheet and wonders aloud why that player isn’t using X, when there’s no reason in-game for Player 2’s character to know about X. This is particularly onerous when Player 1 refuses to use power X because she doesn’t think her character would use it in that particular situation.

I’ve also seen cases where OPC gets really obnoxious. I’ve seen players demand to know why other players aren’t spending XP (usually with several suggestions on how to spend it) or players starting vendettas against other players because power X wasn’t used and it screwed over a player.

There are occasions when OPC can be a boon. Besides the aforementioned inexperienced player, there are players that simply can’t be bothered with remembering things outside of a session (they’re lucky if they remember what character they are playing when they arrive). This is especially an issue for one-shots or irregularly-scheduled campaigns. In these cases I find that OPC eases my burden as a GM.

So how about you? Do you regularly slap down OPC in regular campaigns when all of the players are experienced, or do you let it slide? Have you seen any especially good or bad uses of OPC in your campaigns?