I am now convinced this is on a Walmart by Walmart basis because frequently, I am able to just walk right out the door.. I let my body language speak for me like okay I am prepared to show my papers as that is how most people that just got done spending more of their money than usual purchasing something would feel.. and they usually make no effort to stop me, or look. Frequently even a have a nice day, we are all pleasant and friendly folks. Even if not, more often than not, if I have bags and just went through self check-out and was just on video camera at the kiosk buying things, they tend to know. Or if you are in there all the time. Still, even if I am at a Walmart somewhere I have never been.. only sometimes, do they actually check my receipt. And it is a store employee that does that, not security. They have a whole office with a guy or two just waiting to go approach someone as pseudo-law enforcement if anyone wants to protest, it is right by the entrance and exit. They know if you have been stealing. At least Walmart in this day and age does.
And I used to steal things at Stop and Shop so I appreciate the discretion.