If you've got fantasies of beheading an Xbox 360 avatar, then using yours to steal a car and run over babies while you drive to your friendly neighborhood drug dealer, where you score a bag of dust and proceed to get dusted, I've got bad news for you. Firstly, you'll be hearing from my lawyers, who will inform you to get out of my head. Secondly, Microsoft has issued a list of things those cartoony things are forbidden from doing.
Specifically, the list, which comes to us by way of OXM UK, has been issued to developers in the XNA Indie Games program. Any of those formerly-known-as-Community-Games games that happen to use the system's avatars have to go through a peer review process to make sure they aren't crossing the line.
Where's the line, you ask? Most of them are pretty standard stuff, like violence that goes beyond what you'd see in a football game, or "excreting obscene bodily fluids or substances." There goes that avatar-based version of Don't Shit Your Pants I was working on...
But then there are a few guidelines that are aimed at the sanctity of the experience. Avatars aren't allowed to have their own identity. Since they're supposed to be a representation of the player, they aren't allowed to really break the fourth wall and attempt to interact with the player.
And then there's this one. "Avatars may leave innocents or bystanders slightly injured, but not dead." Weeeeak. What, you wouldn't pay 800 points for a multiplayer third-person shooter where the avatars blow each other to gory little bits?
If you're interested in the rest of the list, it lives on over here.