Originally Posted by sxpsxpsxp
First the disclaimer: I am not a lawyer.
My understanding is that the justification for all the security searches, and certainly for any type of a lie-detector type machine when entering an airport is that you are submitting to such searches voluntarily.
You are correct; however, this recent test if Knoxville was "only a test" and pax apparently could refuse to participate. I'm certain if the TSA ever introduced it as a screening mechanism, no one would be able to refuse.