The next section is a half page or so section titled "Players are not characters!"
Looking at the title, and considering the "Satanic Panic" and BADD and steam tunnels and what not, you'd think it would be yet another place where the game tries to allay the fears of any parents who might be looking over their children's books. Got to keep your head straight about the game. Right, Marcie?
What we actually get is a brief reminder that you are not your character, and that while you know all about the game mechanics and other stuff going on, you shouldn't use that player knowledge to metagame advantages for your PC.
Try to get into your character's head, and think like your character would, rather than making all your decisions based on game factors that your character might not know about. You may even want to make a bad decision if you have a mentally weak character or are playing a Chaotic. And the other players should remember to be cool with that as players, although it's perfectly fine for them to have their characters be upset with the stupid or untrustworthy character.
Dungeon Masters should also keep an eye on things, and remind players from time to time that their character wouldn't know certain things that the player does, to help keep them from taking advantage of metagame knowledge.
So, not what you'd think when you read the title.
Of course, I actually have some concerns about a game in which no metagaming takes place at all. Part of the fun is meeting the challenges in the game and outwitting them through your own keen thinking as a player. Or at least it is for me. To an extent, metagaming is necessary for an RPG to be a game.