I agree. It seems to me that the speciality of the Necomb Problem is that actions "influence" states and that this is the reason why the dominance principle alone isn't giving the right answer. The same applies to this game. Your action (sim or not sim) determines the probability of which agent you have been all along and therefore "influences" the states of the game, whether you are X or X*. Many people dislike this use of the word "influence" but I think there are some good reasons in favour of a broader use of it (eg. quantum entanglement).