(In fact, I always thought that the strategy 51% one-box 49% two box would game the system, assuming that Omega just predicts the outcome which is most likely).

Incidentally, my preferred version of Newcomb is that if the Predictor decides that your chance of one-boxing is p, it puts (one million times p) dollars in the big box. Presumably, you know that the Predictor is both extremely well-calibrated and shockingly accurate (it usually winds up with p near 0 or near 1).