Now that is a first: I have to disagree with Bruce Schneier.
“4. I think airline passenger screening is inane. It’s invasive, expensive, time-consuming, and doesn’t make us safer. I think that civil disobedience is a perfectly reasonable reaction.”
Of course there are millions of ways how people can get stuff into the plane anyway, but this makes it a hell of a lot harder, which is the idea. Like virus scanners on PCs – you won’t catch everything, but everything you do catch can’t do wrong anymore.