And then there are other statistical hangups that would be unique to this market and probably make it much not really comparable to, and much less effective than, any previous one.
But it just occurred to me that we might have lost an ironic payoff by not letting this go ahead. If people had to bet real money on whether they'd be a serious terrorist attack in the US in the next 12 months, I daresay the odds against it would be pretty high. And as the years went on, they'd get higher. It might have been a nice "objective" antidote to the government's constant attempts to incite panic. (Remember the good old days, when the UK govt. used to tell the people that panicking would only be letting the terrorists win? Those were the days.)
Personally I have a 10 year bet starting in 2004 that more people will be struck by lightening than killed by terrorists in the US over that period. And the only guy I could get to take the other side did so mainly out of an impish sense of humor.
Michael