Once the door is open, what stops the "buyer" from just grabbing everything of value? It appears to be like a hotel MiniBar concept but with no way to check in

Once the door is open, what stops the "buyer" from just grabbing everything of value? It appears to be like a hotel MiniBar concept but with no way to check inventory after a customer departs, resulting in shrinkage. Another risk is that even an honest buyer can get blamed/charge for subsequent theft.