BTW I quite enjoy the passive aggressive questions. If they ask if I know the machine is safe I always agree with them that the machine is safe. They find that amusing in SFO and annoying in BOS. I don't fly through LAX so they might be more annoying there.
I find that most of the time the TSA people, if you treat them with a bit of a sense of humor, are usually pretty nice about the whole opt out thing (though they do do the passive agressive stuff). However I'm white middle aged guy with a wedding ring. So perhaps I get, by far, the easiest side of TSA 'attitude'.