I was under the impression that in Prisoners' Dilemma, the punishment for the "sucker" was supposed to be more extreme than the punishment if both prisoners rat on each other.
Player 1, Player 2
C D
____ ____
C|1, 1|0, 1|
D|1, 0|0, 0|
In order for this to be the Prisoner's Dilemma, only defect must be in NE, see: http://en.wikipedia.org/wiki/Prisoner%27s_dilemma
It does follow the rules of prisoner's dilemma, as far as I can tell.
(Found via the link to the original paper, http://www.plosone.org/article/info:doi/10.1371/journal.pone...)
Pun intended?