There was a 63 split window locally that got all the gell coat sanded off and then left outside in raw fiber glass. Later got "saved" with bodywork and a LS swap.
I once did a C2 Corvette for a guy that needed to be sanded down before I painted it. I gave him a price, but he wanted to pay less, so I told him if he would sand it down, I'd reduce the price. He brought it back to me all proud of his work. He had used paint remover and a putty knife. The car had gobs of balled up paint and LOTS of putty knife gouges all over the car. I painted it, but it cost him a lot more than if I had sanded it myself.