Walmart near me has started using receipt checkers lately and they don’t even really do their job, it’s kind of a gimmick really. They just look at the receipt for a second Don’t even look at your cart, but they stop you every time. It’s just such a waste of my time when I’m in a hurry. I had one person even tell me that it was required by law. No it’s not! There’s no law in the USA that says they have to check your receipt.
Just look pissed off and walk by as though they don’t exist. They’ll never bother you.
They don’t get paid enough to fight and they know it.
They cannot legally prohibit your egress. If you signed a contract agreeing to checks, I guess they could cancel your membership or whatever the contract says.