The FBI just recalled its manhunt for five Middle Eastern men (actually 12, but they had photos of five) that supposedly snuck into the U.S. from Canada. The first public sign that perhaps this alert was less than credible was when a Mr. Mohammed Asghar contacted U.S. authorities from his home in Pakistan to say that he was one of men in the photos, and he was still home in Pakistan and they had the name wrong. Eventually, the information from an arrested immigrant smuggler probably trying to get a better deal for himself, turned out to be false.

A little lesson, not only about the limitations of using criminal informants and premising plea bargains on providing evidence to law enforcement but also about our own credulousness. I don’t blame the FBI for being careful. But we have to be careful about carefulness, to make sure that we don’t believe a story because it sounds so plausible, rather than because there’s actually evidence that its true. There is vast danger in “protecting” ourselves against credible but ultimately imaginary threats, and ignoring the unexpected, but real, dangers.