They've been around long enough now that you'd think the manufacturers could have ironed out some of the teething problems. But they just seem to be so pedantic about stuff that really doesn't matter.
Why the frick does it matter if there's an unexpected item in the bagging area? Its not a security risk? Why can't I, once I've scanned the fecker, just put my newspaper and my croissant into my own bag without having to put it the sodding bagging area without the entire thing melting down? Why do I need authorization to buy a single can of lager when I'm old enough to be the grandmother of most of the employees in the shop?
These supermarkets bleat on about a) customer services and b) cutting operating costs. And yet these things make life infinitely more complicated and drive people like me to the point where I have to be restrained from taking a hammer to them.