"There is something spookily appropriate about having an airport security officer lie to you in order to try to violate your civil rights, even in a relatively small way, when you are en route to a convention about technology and freedom.
This morning, as I was going through a deserted security screening post at MIA, in terminal C, just as I was about to put my luggage through the X-ray, the TSA guy working the outside of security, who had already passed me through, decided to invite back in order that I could step through the "puffer machine," more formally known as an EDT (explosive detection portal) or ETP (Explosives Trace Portal). I wasn't marked for a security screening, and I suspect nothing more was going on than the guy was bored and wanted something to do. Knowing that I have the right to refuse (at the cost of being searched by hand), and having plenty of time until my flight, I told him that I didn't like the look of the machine, and I would rather not. This is where the trouble started.
Rather than warn me that the consequence of failing to consent would be a search, which would have been a legally correct reply, or even decide that I would have to be searched whether I wanted to be or not, which might have been legal too, the guy told me that I had no choice, that I had to go through the machine. I told him that I knew for a fact that this was not true, that I had a choice. He insisted. I asked him to get his supervisor over. He did. I explained the problem..."