In my supermarket they are mandatory. You get your fruit and you put them in a scale which prints out an sticker with the weight, pricing and barcode, which is what os scanned at checkout.
This would be all avoided if they had scales at checkout and the clerk used them (which would also reduce fraud) but of course is cheaper having way less staff.
The hate for mods is quite insane. I can understand that there were some instances of power abuse and people should be critical of those, but I dont think the widespread hate they get. It's a lot of work that people don't realize, and people hating them just because polls for closing or taking action dont turn out exactly they wanted (and, if politics is any indication, probably many of them didnt even vote), to a protest in which, as normal users, they dont have to do anything... its all insane to me.
The problem is that people ever bought enough gold to cover costs.
Admitedly, its also reddit problem that they went from hosting links/text to also hosting images/video which is a completely different (and more expensive) beast.