I used to do this (something kind of similar) at the Shaws Supermarket at the Prudential Center in Boston when it first opened, but with wine. When that store opened, it had the first self scan checkout in the city with NO security cameras above them and the weighing features never worked right. Prime pickins for a good scam.
Anywho, how it worked, is I'd buy like 16-24 bottles at a time, most of it fairly cheap shit, but with 2 or 3 bottles of really expensive champagne thrown into the mix. The first bottle I'd scan, the self checkout would announce, "Approval needed." Some lackey would come and check my ID, and then remove the anti theft plastic tops from all the bottles at the same time, and just leave. Then I'd scan them quickly, putting one in each hand, and bag them quickly, just to stay on the safe side/in case any security was watching, and then put the bags back in my cart. The only thing was, I'd angle the bottles so that the expensive bottles didn't scan, and then just bag them. I'd always scan the wine last so I could make a quick, smooth exit. Down the elevator and into a cab I'd go.
There was a point during my senior year in college that I was routinely boosting $4000 USD in bubbly a week and reselling it for $3000 or so to less scrupulous nightclubs, bars and consumers. I never got caught.
I let a close friend in on the secret, and he basically did the same thing, except with all expensive shit, didn't pay for a third of it, and was busted, but got off and was let go simply feigning ignorance of how the self check out system worked, saying he hadn't used one before and couldn't tell whether a beep was originating from his machine (saying something had scanned) or someone else's machine. The store bought that and let him off on two different times (he simply made good on the purchase before leaving and walked free.)
Nothing tastes as good as drinking ice cold vintage Cristal straight from the bottle like it was a beer at your fraternity party. Especially when you didn't pay a goddamned thing for it.