Not exactly "retail," but I did work in a movie theater for several years and you would not believe the things customers would do in this place. We found buckets of chicken bones, condoms, dirty diapers, underwear and all kinds of other clothing, money, bags of merchandise from nearby stores, baby seats (???), cameras, soggy tissues, chewing tobacco, cigars, drugs. The list goes on.
One of the funniest things that happened was when some kids took a fire extinguisher into one of the theaters and cut loose with it in the entryway, so it looked like an ice cave. The fumes filled up the theater, and the fog was so thick that the image from the projector was imposed on the cloud instead of the screen. A few people thought it was some promotional thing -- I think we were showing The Prestige or The Illusionist at the time. We had to evacuate and refund everyone in that showing.
The following weekend, they did it again.