"The archaic system of an X-ray machine and metal detector cannot pick up other potential threats posed by passengers," Baum says. "I can have a ceramic weapon or chemical weapons and walk through an archway metal detector and it won't be picked up. Yet we have huge faith in these metal detectors that can only pick up one substance."

Metal detectors are blacklists, but I'm nto sure if things like Layer Voice Analysis can be called whitelists. We need a whitelist device for airport security.

Behavioral screening -- the future of airport security? - CNN.com