In a blog update (http://www.schneier.com/blog/archives/2012/03/congressional_t.html), Bruce Schneider says that "at the request of the TSA" he was removed from the witness list.
Bruce also said "it's pretty clear that the TSA is afraid of public testimony on the topic, and especially of being challenged in front of Congress. They want to control the story, and it's easier for them to do that if I'm not sitting next to them pointing out all the holes in their position. Unfortunately, the committee went along with them."
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