There was this interesting article on this idea of terahertz lasers in airports. I think these machines are great because they are programmable and specific. You can program them to look just for explosives and this reduces the search issues significantly. But what of the fact that they would mean the TSA might be Constitutionally barred from looking for drugs? Would this retard adoption?

I think if you want to show you are doing a great job at law enforcement and minimize the warrant requirement, you want to have as many false positives as the courts will let you get away with. "Yeah they only found a few oz of pot, but they had probable cause to believe he was a sexual predator, so the evidence is admissible."