This seems like a clear example of "You shouldn't adjust the probability that high just because you're trying to avoid overconfidence; that's privileging a complicated possibility."
Reading this comment made me slightly update my probability that the parent, or a weaker version thereof, is correct.
I was very interested in the discussions and opinions that grew out of the last time this was played, but find digging through 800+ comments for a new game to start on the same thread annoying. I also don't want this game ruined by a potential sock puppet (whom ever it may be). So here's a non-sockpuppetiered Irrationality Game, if there's still interest. If there isn't, downvote to oblivion!
The original rules:
Enjoy!