> I fill a cart, walk through the gate out the door and receive a total, passing my card/phone over a sensor to pay.

More technology? Maybe the wrong direction.

Oldest "hack" in modern shoplifting is to swap the contents of the boxes. You open two boxes on the floor, swap tools, get the better tool charged for the lesser-priced tool.

Or as you suggest, merely remove the identification tag so it is not charged at all.

Maybe just bring back cashiers to ring people up?