I'm not talking about your sort of case at all. A small incidence of opt-outs, whether for medical or political reasons, does not choke the system. (When the backscatter devices were deployed I always opted out myself.) I am taking issue with people who favor mass protest action that deliberately paralyzes the system. it is one thing, and a fine thing, to avoid the devices on grounds like yours. It is a dumb thing to wreck the functioning of a whole checkpoint in the mistaken belief it will make dumb security go away.