Briliant step up on a smash-and-grab.

Bruce Schneier wrote:
"Attackers commonly force active failures specifically to cause a larger system to fail. Burglars cut an alarm wire at a warehouse and then retreat a safe distance. The police arrive and find nothing, decide that it's an active failure, and tell the warehouse owner to deal with it in the morning. Then, after the police leave, the burglars reappear and steal everything."

http://www.schneier.com/blog/archives/2006/09/burglars_foil_a.html

One time where I used to work (about 10 years ago) the security alarm went off in the middle of the night. The security company claimed they came out to the office and everything was fine. In the morning a few laptops were missing and it looks like beer or some sticky fluid had been poured over a few of the keyboards. Oh and there was a giant hole in a floor-to-ceiling window.

At the time I thought it was incompetent security people. Maybe it was slightly brighter than average criminals.