One way I would think about PrudentBot is as not trying to approximate a decision theory, but rather a special consideration to the features of this particular format, where diverse intelligent agents are examining your source code. Rather than submitting a program to make optimal decisions, you submit a program which is simplified somewhat in a way that errs on the side of cooperation, to make it easier for people who are trying to cooperate with you.

But something about my reasoning is wrong, as it doesn't fit very well to the difference of the actual codes of ADTBot and PrudentBot.