If you find yourself on a playing field where everyone else is a TrollBot (players who cooperate with you if and only if you cooperate with DefectBot) then you should cooperate with DefectBots and defect against TrollBots.

An example from real life: DefectBot = God, TrollBots = your religious neighbors. God does not reward you for your prayers, but your neighbors may punish you socially for lack of trying. You defect against your neighbors by secretly being a member of an atheist community, and generally by not punishing other nonbelievers.

I wonder what techniques could we use to make the compartmentalization stronger and easy to turn off when it's no longer needed. Clear boundaries. A possible solution would be to use the different set of beliefs only while wearing a silly hat. Not literally silly, because I might want to use it in public without handicapping myself. But some environmental reminder. An amulet, perhaps?