I wonder how extensive this scamming actually is.

Every Walmart I ever walk in always seems to have 20 people in the Returns line.

People suck!

I have received items from amazon a few time that were returns not new. No problems with replacement from amazon. The last item they just replaced and told me to throw away the used item. All items have been electronic.

Many stores use the same method to deal with returns, refunds, problems etc: Put the slowest, dumbest mouthbreather on staff behind the counter. Train them to say “no”. Ensure there’s always a long line to wait in and that the wait will be extended and that the whole process will be distasteful and laborious.