The vast majority of the problems with self-checkout machines are caused by the item weight check. Try shopping in the better part of town.

In the UK, self-checkouts in Tesco and Sainsbury's (where the poor do their shopping) will have this up to 11, whereas Waitrose (for affluent people) turn it off. So you can steal as much as you want, too, since there's only 1 person looking after 6 machines (when there's anyone at all).

Only time I've been happy to pay the premium to shop there.