I am breaking my "only comment on LW if you expect some benefit" rule because I am in a somewhat unique position to comment on this, and I agree with Eliezer that "penalizing people for sounding certain or uppity or above-the-status-you-assign-them can potentially lead you to ignore people who are actually competent". See, I made this update at an earlier time under not-dissimilar circumstances. (In short, I thought ArisKatsaris was making an overconfident prediction about HPMoR, bet against him, and lost.)

An excerpt from my journal, 3/28/2012:

Well, I lost my bet. But what did I learn? Give less probability mass to “some unknown possibility no one has thought of” when the number of people thinking is sufficiently large. Also, arrogant people may be arrogant because they’re usually right, so be careful of the impulse to smack them down.

So, you know, here's a chance to learn a $30 lesson for free, people.