Thanks for the explanation. I think that if the right decision is always to 2-box (which it is if Omega is wrong 1/2-epsilon of the time), then all Omega has to do is flip a biased coin, and choose for the more likely alternative to believe that I 2-box. But I guess you disagree.

There's a true problem if you require Omega to make a deterministic decision; it's probably impossible to even postulate he's right with some specific probability. Maybe that's what you were getting at.