This. It is (petty) theft and I've seen people let go over a "free" soda. It is usually the highest marked up product, a small cup might be about 30c-50c? (Inc cup, lid, straw and drink) But sells for up to a few dollars. Small actual loss but huge loss of profit. Like I said, I've seen people fired over not paying for a small cup because its considered theft. Couple of things, ask your boss if maybe it would be an idea to put up a sign next to the drinks, also ask him if maybe other staff could politely tell customers off w  248b  hen they notice this behaviour? Good luck with it OP