the aggressive policing of these types of errors is what did

Honestly Walmart is weird with theft. In my area pretty much half of everything is under key, it's so annoying. You have to press a button to call an employee who doesn't come, then hunt for one because they have so few, then the employee is annoyed... OK next item now. Oh great it's under key too. Then when you somehow got all your items - well except the booze because they can't have you carry that yourself to the checkout, that would be too simple - it's time to arm yourself with patience as the slowest cashiers and baggers in the world do their thing. Now time to pay... oh hey they're the last store in the western world that doesn't take contactless. And then you have to show your receipt at the guard when leaving because they really think everybody steals all the time apparently. The whole experience is simply unpleasant.