In the interest of seeing what strategies like U and C1 could do regarding experimenting with the opponent's behavior, I would be interested if there were a prisoner's dilemma variant that had a second score that is worth less points but can still add up, enabling a strategy to come out on top if it comes down to neck-and-neck. Real life kind of operates like that: there are ways to win little victories over others, but those strategies are often telling about your character.