You'll see a lot of press about how noone opted out; the TSA Twitter account is retweeting like mad all the people happy about how quickly the lines went Wednesday. A closer review reveals that the the TSA turned off many backscatter machines—there was no need to opt out, so no one opted out. It goes very far to demonstrate how unnecessary these machines are: if the machines were really critical for safety, rather than for public relations, then one hopes TSA wouldn't play with our safety so. But when push came to shove, the TSA was more concerned about the threat to its illusion of security theater than it was about the threat of an attack by terrorists. If every day were Opt-Out Day, the TSA would turn the machines off permanently. More at the TSA Abuse Blog.