Adding to the confusion, TSA considers "non-physical interference" with screening a fine-worthy offense:

http://www.tsa.gov/assets/pdf/enforc...nce_policy.pdf

Nobody has ever given a good definition for that. I doubt they ever will.

It seems like a catch all contempt-of-screener charge similar to contempt-of-cop charges like disorderly conduct. It probably includes things like exercising your right to free speech or asking hard questions. Or using Jedi mind tricks to change the outcome of screening. ("These are not the shampoo bottles you're looking for. Move along.")