A friend forwards the following from Blogger Bob via the Economist:
Speaking of good catches, did you know that our officers have found 725 firearms in carry-on luggage since January of 2011? And it’s still only September!
So that's about 1000 firearms per year. (!) There are that many absentminded American gun-owners who totally forget that, oh, whoops, you can't bring a gun on a plane? It mentions a 1-2% failure rate which seems, actually, sort of okay—in other words, a would-be terrorist would be caught 49 times out of 50 trying to sneak stuff on board, which seems like a pretty good deterrent.
Of course, the body scanners do precious little to find the guns. No one here (that I know of) is arguing against WTMDs at airports. You know, because they actually do something.