We used a purpose-made cover from one of the major suppliers on a motorhome, and it scuffed the shine off the sides in about 3 places. Even though we used all the fixed securing points on it, the company absolved themselves of any 'blame', by insisting it had not been secure enough in winds. To do this it would have needed additional straps something like every 6 inches along the length to prevent 'rippling' of the cover, which caused the scuffs. This being completely impractical, if not impossible.
It was a good cover, with a 'soft' lining, but it still caused damage. I swapped it for a case of beer!