http://www.schneier.com/blog/archives/2010/11/tsa_backscatter.html Schneier is a security expert (albeit mainly data security and encryption) and has been a leading opponent of TSA procedures pretty much forever. I'm actually a little bit surprised he gets through checkpoints at all, he's been so vocal.
(Some of the article is also boosterism for Bruce himself, because he's oft-quoted, but hey, it's his blog, and he can requote himself if he wants to..."