Reminds me of a story, set in a lazy Mark Twain river town. Two friends walking down the street. First says to second, "See that kid? He is really stupid." Second asks, "Why do you say that?" First answers, "Watch". Approaches kid. Holds out nickel in one hand and dime in the other. Asks kid which he prefers. "I'll take the nickel. It's bigger". Man hands nickel to kid with smirk, and the two friends continue on.

Later the second man comes back and attempts to instruct the kid. "A dime is worth twice the value, that is it buys more candy", says he, "even though the nickel looks bigger." The kid gives the man a pitying look. "Ok, if you say so. But I've made seven nickels so far this month. How many dimes have you made?"

Which brings me to my real point - empirical research, I'm sure you have seen it, in which player 1 is asked to specify a split of $10 between himself and player 2. Player 2 then chooses to accept or reject. If he rejects, neither player gets anything. As I recall, when greedy player 1 specifies more than about 70% for himself, player 2 frequently rejects even though he is costing himself money. This can only be understood in classical "rational agent" game theory by postulating that player 2 does not believe researcher claims that the game is a one-shot.

What is the point? Well, perhaps people who have read about Newcomb problems are assuming (like most people in the research) that, somehow or other, greed will be punished.