A flash rob (or flash robbery) is a crime in which a large group of people – usually teenagers – converges to steal items from a store and then disperses as suddenly as they gathered.
The crime is a variation on a flash mob, which is a sudden and seemingly spontaneous gathering of people for some special purpose, such as a surprise dance performance in a train station or a protest demonstration. Flash gatherings are often coordinated – at least in part – through electronic media, such as social networking sites and cell phone text messages.
In a flash robbery, the thieves generally behave casually, as if shopping. At the appointed time, however, they exit the store without paying for items. Because of the number of people involved in a flash rob, it is almost impossible for the store owner or employees to do anything to stop the robbery. Also because of the number of people involved, police sometimes approach cautiously, leaving thieves enough time to get away from the location.
In August 2011, the National Retail Federation reported that 10 percent of retail businesses polled had been the victims of a flash robbery.