I worked retail, and I think that I forgot to remove one about twice. It usually happened on a big bulky item or when some sales associate thought they'd hide the thing. For the store I worked in there were certain rules about when you put the sensors on. So, it wasn't on everything. I always felt horrible about it. Being a manager, I dealt more with the customers with items that I didn't deal with. I really enjoyed the ones who were understanding to the problem. I was really annoyed with the ones who thought we were stupid. Knowing how often something like that can happen I usually didn't question the customer when they came in. I even did a big no-no a few times. I would take them off for other stores. For those, I would look at the receipt.