I started using grocery self-checkouts during COVID, but I’ve kept using them because there’s rarely a line (and I’m a misanthrope). I’d probably go back to using regular human checkouts if I had to dig through all my crap to prove what I bought.
Having said that, I’ve noticed myself making mistakes. I’ve accidentally failed to scan an item, and I’ve accidentally entered incorrect codes for produce. When I notice, I fix them, but I’ve probably missed a few.
I guess the easiest answer is for grocery chains to reinvest some of those windfall profits and hire more cashiers.
FYI to anyone here, you don’t have to show them your receipt or let them check your bag. Just refuse and leave.
Any before anyone says “they’ll ban you from the store”, they very likely won’t. And even if you are added to the ban list, it’s not really possible for them to enforce. I worked at a very high traffic Loblaws for a while as a self checkout attendant, and I would regularly have my friends in customer service point out people that had been banned checking out with no problems.