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.
My local No Frills has shut down their express lane and directs people to their newly built self checkout. It’s basically the express lane except instead of the cashier scanning my items and taking the payment. I scan the items and give payment while a cashier hovers over my shoulder to make sure I’m not stealing anything