we used to do this when i was at my uni job. Shrink wrapped a fiesta once all the way over. Out plasticine in the door locks and a potato in the zorst

funniest thing tho is when people handed their notice in they would get jumped and shrink wrapped from head to toe. If they put up a fight they would get wrapped to some shelving for a few hours or like some poor bugger where he got wrapped up and thrown on the shop floor only for customers to wander past looking funny at him