Eh when I was a hoodlum living through rough times I would steal from Wal-Mart. I'd just go to self checkout and scan a few items while bagging others and I'd walk up to the person at the door and hold my receipt out, unprompted, and they almost always waved me on.
Not saying I'm proud of it, but I had many methods for slipping by them, not just the above. Those employees usually just irritate customers that did the right thing and paid for all their stuff.