That does not surprise me. Airport security is no different than airline safety procedures in general - at the time of landing, a plane travels at approximately 180 mph so if it slams into the ground of water, everyone inside will be dead from internal injuries (e.g. your brain smashing against you skull) with or without belts, safety jackets etc. The only useful safety feature on board is the barf bag - it can actually save your or your neighbor's clothes a seat or the floor .
The same holds for security checks. There is no way these checks can prevent a determined hi-jacker from smuggling things that can be used as lethal weapons, because the effect of a weapon depends largely on the skill of the user. You can kill or seriously injure a person with a plastic knife or even your fingers e.g. by sticking them into your opponent's eyes if you know how to do it. You can place on board several persons with sufficient knowledge of karate who can use their bare hands to defeat anyone, even a person with a gun.
In short, there is NO technology available to prevent another September 11 style hijacking - if the hijackers are well organized, well trained and determined to die for their cause. There is nothing that the almighty US government and security apparatus can do about, no matter how hard they try. At best, they can make it more difficult for the would be hijackers, but not to stop them.
The reason why airlines and security people do the security checks is mainly symbolic - to assure the public that it is safe to fly. This is a purely ritualistic response to danger - akin to that described by the anthropologist Bronislaw Malinowski among Triobran islanders. The islanders had elaborate rituals before they set out for open sea fishing expeditions, but none before they went for inland fishing. What explains the presence or absence of rituals is the possession of technology to prevent the disaster. They had such technology in case of inland fishing, but did not in case of open sea fishing.
The modern man reacts quite similarly as the so-called "primitive" man - as many riwsk management and disaster preparedness rituals suggest e.g. in case of nuclear power plants or oil spills (see Lee Clarke, _Mission improbable :using fantasy documents to tame disaster, U of Chicago Press, 1999) or airline safety.
wojtek