Yes, of course I thought of that when considering my reply, but in this particular context (where we're considering counterfactual dealmaking presumably because the idea of pulling such a stunt in real life is amusing), I thought it was more in the spirit of things to be trusting. As you know, Newcomblike arguments still go through when Omega is merely a very good and very honest predictor rather than a perfect one, and my prior beliefs about reasonably-well-known Less Wrongers make me willing to bet that Simplicio probably isn't going to lie in order to scam me out of forty-three dollars. (If it wasn't already obvious, my offer was extended to Simplicio only and for the specified amounts only.)