If a BDO could tell instantly when somebody was lying, he would have better professions to enter:

http://www.allvegaspoker.com/

It CAN NOT be done with any sort of accuracy. The questions are going to be a huge annoyance. Ask me if I'm coming back from vacation while wearing a suit and tie and I WILL get annoyed. A great deal of people would, because it shows you are just stupid.

We need a trusted traveler program, body scanning for secondary ONLY with opt-out option, and a massive downsizing of the TSA with focus on intelligence and organized threat detection. Nothing else, no more toys.