Personally I think that Romney has a ~33% chance of victory. That’s not a sufficient margin for me to make a 50:50 bet under these circumstances.
But if a poster claims they are absolutely positive that Romney will win, I think it’s fair to ask them to put something tangible where their mouth is. I asked Bricker once to give me 3:1[?] odds on this election. He replied that he wasn’t 3:1 confident: he was even money confident. I thought his answer was honorable.
OMG hems and haws. I think he’s full of horse pucky – but so are most people when asked to back their opinions with something tangible, even if it’s of rather symbolic importance. In other words, most bold pronouncements in real life and on political television are BS. Not all though. Nate Silver pointed out that the predictions on the McLaughlin Group are equivalent to coin tossing. And some pundits (Dick Morris, IIRC) are worse (though a few are better - Clarence Page, for example).
I’ll add that the OP is ignoring transactions costs. Personally, I’d be reluctant to bet with prr as I don’t trust his character and I wouldn’t want to negotiate a friendly wager with him. Furthermore, bringing up the betting subject is a method of deflating blowhards. Once they turn you down, the job is over: there’s no need for a pit thread: they’ve already demonstrated their phoniness.