According to the FBI, terrorists have noticed that Americans will go crazy and attack themselves (shutting down public spaces and transit, evacuating busy areas, subjecting innocents to search, detention and questioning) if you leave a "suspicious" bag in a public place. This is thanks to programs like New York City's "See Something, Say Something," which generates thousands of calls about "suspicious activity" every year, not one of which has ever led to an actual terrorism arrest. Of course, leaving bags of water or socks is an errand that's a lot less risky than planting bombs.

New terrorist tactic: Suspicious bags?

(via Runnin' Scared)