I do not think Bachmann and Perry are double-crossing Sarah Palin at all. If anything, by putting themselves into the race early, they are helping Palin keep her options open by keeping some RINO (like Romney) from becoming a front-runner early on.
If and when Palin does get into the race, she will immediately become the front-runner and be able to easily absorb the organizations and resources that candidates like Bachmann and Perry have already built. Also, Bachmann and Perry are obtaining some visibility and experience on the national stage so that either of them would be good running mate candidates once Sarah is nominated.
I likek that logic. Although Ed Rollins is a creep.