What always gets me in experiments offering gambles is the implictly unquestioned assumption that it's rational for a subject to assume that the claimed odds of a bet are in fact the actual odds of the bet. That would certainly make the analysis much simpler, but a tempting simplification isn't necessarily an accurate one.

Yes. I think I already mentioned that the real reason why I wouldn't take a 50% chance of winning $110 and 50% chance of losing $100 is that if someone is willing to offer such a bet to me, then they most likely know something about the coin to be flipped that I don't. If I was offered such a bet in a way extremely hard to cheat at (say, using random.org), I would happily take it -- but I don't expect anyone doing that, anyway.