I worked as a supermarket cashier at a local store which was signed up to have secret shoppers come in. In this case, it was to see if they could get away with cheating or stealing from the store. They would test us on the kinds of things we had been trained to look for: taking their word for it rather than doing a price check, not checking for the bag of pet food on the bottom rack of the cart…I fell for all of the tricks but got to keep my job because they were hard up for help. :o