I worked there all through college and after for a total of ten years. Its a very organized LP department who has their ducks in a row, where they actually have a training program. When I started it was 10% internal cases, and 90% shoplifter. By the time I left, it was reverse.
We ran investigated some pretty neat stuff from idiots who use Sears like a tool rental (aka constant buy and return ration of 100% with item being used) and shutting them down; folks not using the pick-up kisok on purpose and then trying to get a second item or "retunring" something they picked-up whihc did not show; associates who gave unauthorized discounts; associates mis-using their discount cards; associates stealing from the till; major shoplifting/return rings; etc.... A guy stealing the boom box with a retail price of $200 cost the store about $75, yet the associate who rings them out is taking $100 a shift from the till! The internals and major scams cost a lot more than the rare shoplifters. Besides, a good floor associate can deter most shoplifting.
Wear a suit...be honest and open and you will be fine.
-In God we trust. All others, put your hands on the car and don't move.