People will make a big deal out of 'the bet', but in reality its a non-issue. All he did was call Perry on his accusations and did it in a way that was meant to show he was serious. I don't think he was saying that 10 grand was chump change, I think he picked a serious amount to show that he was serious about Perry being wrong.
Was it a miscalculation? Probably. But not because it was a bad statement but because people will misconstrue it and misrepresent it.
How many of us have been in an argument and said something to the order of 'I bet you a million dollars it was 1986 that we beat Miami and not 1985!'?
Now, I can't stand Romney and think it would just be hilarious to see his hair catch on fire while he is giving a speech, but I just can't see that this should matter to anyone. Even though it will.