The machines can be buggy. The one I use (Giant supermarkets) often doesn't ask for a quantity on navel oranges. It just rings up the the price for one and sa

The machines can be buggy. The one I use (Giant supermarkets) often doesn't ask for a quantity on navel oranges. It just rings up the the price for one and says put them in the bag. I don't want to bother the attendant, who's often busy debugging some problem another person is having, so I just put them in the bag. I've probably not paid for a few 10s of bucks on navel oranges this way over the past few years. The anti-theft system is pretty paranoid though. I've tripped up its video alarm a few times just with my normal awkward motions - waffling about which item I want to scan next, while holding it, seems to mess it up. The attendant comes over and we both watch the review video from the camera above featuring a few seconds of my receding hairline, he clears it and I keep going. But I still prefer self-checkout greatly over weird/awkward human interactions, and I can bag at my own pace too and i'm not holding up the line.