[KingMob]

Exactly correct. Why play with cheaters?

The fundamental flaw in applying game theory to biology is to constrain the possible outcomes when unfairness is detected. In game theory, all you can do is change your strategy for the next round; in reality, we have multiple punishments to bring to bear, such as refusing to play, public shaming, fines, imprisonment, killing, etc.

Game theory is only an "ok" model of cooperation/competition in real life.

[elektronjunge]

That's not a problem with game theory. That's a problem with using overly simplistic games. You can easily model all of those punishments with different payouts in a game. In fact, when I studied it in school most of the games we worked through included punishment mechanisms.