Well, I mean, even if the thing has access to a shared PoS DB using properly randomized, sufficiently long and non-sequential transaction tokens, it's still deliciously susceptible to simple malicious compliance: Find the cheapest single item carried by the store, fill up an entire basket with them sumbitches, line up each item separated by a divider and insist on a receipt for each separate transaction to "prepare for any future need to check if the store carries anything i actually want while maintaining strict compliance with store policies". Then, head outside and start distributing whatever it is for free to other prospective customers and use that to strike up a conversation about the recent changes. You never know. People might get ideas.