Many scientists have come out and said that the chances of someone successfully mixing a binary explosive of sufficient strength in an airplane toilet is ridiculously low. It might be easier to arrange for a meteor to hit the plane in mid-flight. But unfortunately it was in the news, and since everything in the news is absolutely accurate, Americans are now afraid of binary explosives. Therefore the government has to do something about this serious threat.

Even backscatter X-Rays (which I'm sure will become standard as soon as the privacy implications have simmered down enough) don't address the problem. There are plenty of things in an airplane cabin (coke cans, broken bottles) that you can turn into a weapon as deadly as a knife.

I wish I could find that article; it pointed out that the box cutters used by the 9/11 hijackers were not particularly effective. The real weapon the terrorists had was the fact that airplane passengers believed, from past hijackings, that compliance was the correct response.