This wasn't me but a guy I knew used to work at a restaurant that sold beer. He was usually the last person to leave in the afternoon when they closed (they only did breakfast and lunch). The way it worked was the boss would lock the doors and leave then he would clean the place and leave, the doors would lock automatically behind him.

One day he decided to steal a case of beer from the fridge. He brought the case upstairs and set it down on the table right in front of the door. He goes outside to pull his car around front and **click**, the door closes and locks behind him. Needless to say he was fired when the boss came in the next morning and found the evidence of his attempted thievery.