Back in the day when I used to be in retail, here's one I'd do all the time so don't be surprised if it's being done to you.
If a customer kept insisting I check in the back for something they wanted in a different size, I'd go to the back but I'd sit for 5 minutes, drink some water, & maybe talk on the phone before I actually went back out and told the customer that we had nothing in the back.
