"This item is scratched, so I want a 50% discount refunded" - comes to my mind. Most of customer service is dealing with Karens
I wouldn't call a person wanting their new item to be in new condition a scammer.
The story that made me quit:
We had an extremely clear policy of no returns or exchange on opened printer cartridges.
A customer came in to obtain a refund. He claimed it was the wrong cartridge.
Did anybody help him or instruct him to take that cartridge? Nope.
Did he notice that it's explicitly not for his printer? Before he opened it? Nope.
I pick up the cartridge and... it's empty. Dry. Nothing left in it.
Before I could even say anything he looks at me, and start yelling and slamming his hands on the counter and making a scene. Not because he was upset, there was nothing to be upset about yet. It was just a rational, calculated move to obtain a refund on a cartridge he fully used. 30 seconds later the store manager comes over and gives him the refund.
Store manager coached me and indicated, this is basically retail life and where he comes in to provides judgment - the disruption and bad image this person created FAR outweighed the $50 he gave away. It was nothing personal and I should not feel bad or betrayed that I was overruled after following clear rules.
I absolutely 100% agree with manager's perspective. He did the right thing. I could not blame him or wish that he did otherwise. The only way I could find for that scenario to have a different outcome was for me to not be there anymore, so I tendered my resignation the next day.