sbrower, while I agree with your basic arguement, I think you are wrong about suicidal employees versus bombs. Off the top of my head bombs have blown up atleast 4 planes. 2 by the Libyans (Air France? over africa and Pan Am), Canadian plane by Sihks and Jap. Red Army with North Korean help on (JAL?).
Suicides Egypt Air, the commuter plane in California and maybe, I think, one in Indonesia. Is there others?
Otherwise I agree that this is an illogical waste of effort for extremely low probability of success. Heavy profiling of checked bags would probably be as successful as wasting all this money rushing to put any tech in place to check every bag.
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Robert