Would they be responsible if your possessions had been stolen while you were being searched? I doubt the security company or airport management cares.

I have spoken to many of the police officers at the SJC AA checkpoint over the past few months. They relax their guard once they know I am also a cop, and have confided the enormous contempt they have for the screeners who work the checkpoint, many of whom have only a rudimentary command of the english language and a contemptuous attitude towards travelers. Most of them feel that a traveler having problems should actually ask for the intervention of a police officer. Instead of a semi-literate green-card holder you will be able to deal with a highly trained, professional police officer accustomed to the discrete use of her or his authority and who actually has a knowledge of what the federal regulations controlling these checkpoints really is. Veteran cops are comfortable with their authority, have nothing to prove, and will rarely over-react or become hysterical. I would recommend their intervention if there was a problem. Once they were convinced your actions were reasonable they would over-rule the screeners and allow you to proceed. Whether the professional police officers will still have this authority after the screeners become federal agents - I do not know.