Fiberglass Fender Protection Question

My Mod/Cub/Kenskill style fiberglass fenders are now painted. In thinking about trying to protect my investment, I am considering having 3m paint protection film put on the fenders.
Before I spend the money, I was wondering where the majority of the rock "dings" come from. Are they from rocks kicked up by the tow vehicle tires, the teardrop tires, or both?
Thank you for your responses.
Before I spend the money, I was wondering where the majority of the rock "dings" come from. Are they from rocks kicked up by the tow vehicle tires, the teardrop tires, or both?
Thank you for your responses.