The best system I’ve tried works by an app. You scan the items with your phone as you pick them up and put them in your bag while still in the app store. Pay in the app and then just leave. They can check your bag if they want to, and there’s camera surveillance.

The self-check out systems don’t really do anything better than that anyway. It a waste of time in my opinion and only encourages people to cheat. They still need to do random checks and camera surveillance.