Hmm, on further reflection, I had an effect in mind which doesn’t necessarily break your argument, but which increases the degree to which other counterarguments such as AlexMennen’s break your argument. This effect isn’t necessarily solved by multiplying the contract payoff (since decisions aren’t necessarily continuous as a function of utilities), but it may under many circumstances be approximately solved by it. So maybe it doesn’t matter so much, at least until AlexMennen’s points are addressed so I can see where it fits in with that.
Replied.