In UK we have supermarkets like Waitrose which do this (QuickCheck) and it works pretty well. You get a random rescan - though haven't been done for a long time

In UK we have supermarkets like Waitrose which do this (QuickCheck) and it works pretty well. You get a random rescan - though haven't been done for a long time (hopefully proved trustworthy in the past!). The smartphone app works, but is much less convenient I find because my phone goes off in between scanning items! One drawback is buying alcohol - you have to wait for an assistant to do override to ensure you are over 18 - can result in a wait. As for the various shops which offer self scan at checkout - most are very poor UX I find. You have to scan things and it is waiting for a weight to be added to bagging area - if you don't put it down it doesn't register. 5 items the same - all have to be scanned one at a time. Then there is annoying voice - I dislike them. Worst example is W H Smith at airports - not helped by lots of less than clued up people using them...