No, they didnt say painting them would cause it to rust, but instead if I buy the replacement part and then they paint the replacement, compared to them pounding out, sanding, and repainting the original damage fender on my car. They said the replacement fender will rust out far faster, implying the quality of the replacement fender is crap, and if I get the new fender for them to paint, that they wont warranty it, claiming it would rust. I suspect it's a scare tactic, bc if I buy the new replacement fender, then all they would have to do is paint it. If they have to fix the damaged fender, then they would be able to bill for far more work at $75 per hour, then also charge for paint which was also expensive.