Bruce Schneier (for my money, the world's greatest expert on analysing security threats) has written in
his blog:
Airport security is the last line of defense, and not a very good one at that. Sure, it'll catch the sloppy and the stupid -- and that's a good enough reason not to do away with it entirely -- but it won't catch a well-planned plot. We can't keep weapons out of prisons; we can't possibly keep them off airplanes.
This cartoon says it all:
