Parfit's hitchhiker looks like a thinly veiled Omega problem to me. At the very least, considering the lack of scientific rigorousness in Ekman's research, it should count as quite dubious, so adopting a new decision theory on the basis of that particular problem does not seem rational to me.
What do you do in Newcomb's problem if Omega has a 45% chance of mispredicting you?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.