I think we are missing the point. This isn't about terrorism, despite whatever they tell us. It has to do with money. As I've noticed walking around Boston the past week, it's not just the pros who have huge dslr cameras with a bag full of big lenses, flashes, etc. Plenty of average joes do too. And these places don't want to put up with the bag checks as well as worry that people will take photos of high enough quality to sell.
But I see this as more of an opportunity for rangefinders. Isn't one of the biggest reasons why we all love rangefinders so much is because they are small and discreet? So then take advantage of that. Yes, I am sure there are some places that may not even let through an X100, but those are the exception. In the past year I have brought my Leicas to concerts, plays, a ballet, an opera, numerous museums in both the US and Europe, and other places I can't think of off the top of my head. Just don't bring 3 bodies and 5 lenses and you should be OK. Yes, even at the Kentucky Derby.
Plus, remember, the power is always with the people. If the KD ends of truly cracking down on everyone with a camera, then if everyone who wants to bring a camera (which would be most) stays home, I guarantee they will change their policy quickly.