Anyone who has worked retail (or especially owned a shop of any kind) knows that shoplifting is part and parcel of the experience. Generally it's called "shrinkage," like the inventory magically shrunk rather than being carried off by thieves.
It's an annoyance, but it's one I haven't had to deal with too much, because of the nature of our business. While we do get a lot of casual traffic, most of the people who would be interested in having our product enough to steal it also have enough of a fondness for the store to pay for it instead.
We've had a couple of packages of dice go missing lately. We know because we find the empty boxes stashed somewhere in a display, the dice obviously slipped into a pocket and carried out. Annoying, but relatively minor.
Then today, my manager and one of the employees noticed that some of our Battle Royale was missing. Notably, the first three or four volumes, and our inventory indicated we had one, and in some cases two, of each volume. Later tonight, a group of four teenagers who have been semi-regulars (although they've rarely purchased anything) came in, and while the manager was busy, they stole three more volumes of Battle Royale. He knows this because they were there when the teens came in, gone when they left, and there were no other customers in that time.
So we know who they are. We know what they look like. And the next time they come back, they will either be read off the property or arrested for shoplifting. Which isn't much comfort as I go to buy about eight or ten volumes of Battle Royale that I already bought, but it will be if we catch them in the act.