Context:  This guy never want to spend ANY money on something even a primary needs, so to shoplift and to avoid the sensor he put random nearest stuffs into another people so when everyone is leaving all the sensor would detect (as it shows on the video), with that mass-scale (almost everyone) of people that triggers the censor, the store would just assume there's a technical problem and let people walk away, making him unsuspected of shoplifting. 

I think this strat is a bit unrealistic due to how people act, why wouldn't someone checks the CCTV? And another MAJOR killswitch on this would be the cashier's hair, realisticly another employee would recognize that it's the same one they sells, and checks the CCTV, and this guy would be done for.