2. The title gestures to that (notice that programmer and prisoner both have 3 syllables, even)
3. The article links straight to the SEP article on the prisoner's dilemma
http://plato.stanford.edu/entries/prisoner-dilemma/#StaHunPD
It could be that in some organizations, the rewards are such that a Stag Hunt is a better model.
Sorry for being unclear.
If mutual cooperation was the best outcome, there would be no dilemma.
[1]: http://en.wikipedia.org/wiki/Prisoner%27s_dilemma#Strategy_f...
Maybe you don't care about "overall best outcome". Maybe you only care what happens to you, in which case I assume you would betray me. But in the face of rules that are going to screw the people no matter what, closing ranks causes the least overall harm -- assuming you have sufficient trust to pull that off in the absence of communication. (EDIT: For example, if you are both members of an organized crime syndicate or a resistance movement, the organization suffers the least overall loss/cost if it gives very strict orders that no one talks -- assuming the two people are of equal value to the organization. Even if you are not part of a larger organization, betrayal costs not only time served but trust of the person you betrayed. Depending upon the situation, one month in jail may be less of a loss than losing this person's trust.)
It's important to not bring too much real-world logic to the matter. What's being discussed is a certain payoff matrix; the "story" of the Prisoner's Dilemma is really just a way to try to wrap the non-math part of your brain around it, but the payoff matrix, exactly as written, is what is under discussion. The payoff matrix where there is a non-zero probability that they will both manage to skate is a different problem, one not necessarily less worthy of discussion, but one that is not the Prisoner's Dilemma any longer.
If you are interested in further discussion, you should google "Iterated Prisoner's Dilemma" for more fun, including stories about computer simulations of various strategies. Prisoner's Dilemma on its own isn't actually all that interesting, it's more useful as a framing device. Iterated Prisoner's Dilemma is actually interesting.
Peace.