As I've mentioned here a few times, I think most of what passes for Airport Security these days is just a show that's staged to make us think something is being done to catch 9/11-style hijackers before they get on the planes. When you come right down to it, there's no effective reason for us to take off our shoes, dump our bottled water, discard our nail clippers, etc. If someone was determined enough that they were prepared to fly a plane into a building, they could find a way to get a pair of cuticle scissors past the metal detectors.
Jeffrey Goldberg has the same theory and he's been testing it…with the expected result.