They obviously don't read much Tom Clancy.
I'll be getting out of town that weekend, primarily because of the additional congestion/crowding in Houston (as well as price gouging) but I've acknowleged that we could be a target. 1 billion people watch the Super Bowl. This time it is on President Bush's "home turf" (Texas) and his father has a home here.
I don't think we'd see a radioactive, biologiocal, or chemical strike. There may not even be any attack on the stadium proper. Hitting the refineries would impact the economy and American's fuel production. The national media would still be here to cover the event/tragedy.
Then again, Houston was one of the first cities destroyed in the movie Independence Day and it wasn't a "big deal". New York and LA will always generate more attention and sympathy. If it happens in flyover country, it's a "regretable loss". If it happens on the coasts it's a "national tragedy".