I had a college professor who was detained for 44 days when he tried to enter the United States because he had been arrested at an Anti-War demonstration in japan. Choichiro Yatani, who is a doctor in psychology and studied at Stony brook Institute was coming back to the U.S. after attending an international academic conference. He had been invited to the conference to give a speech on a paper we wrote that delt with antinuclear activism. When he tried to enter the country he was told his visa had been revoked and that he was not allowed in. 44 days later he was released, it was a pretty amazing story to hear.
The reason I post this is that here is a guy who had done a whole lot less then Mr. Cat Stevens, so I think people need to realize that security comes at a cost.