There are so many different car shapes and sizes that I think it is impossible to provide reliable parking space protection. I’ve decided life is too short to worry about minor dints, and I usually keep a car for 7+ years, by which time the resale value is not much influenced by them. I did once damage an adjacent newish Jaguar on a windy day and left a note with contact details. I received an e—mail from the owner saying he wouldn’t have noticed it, and anyway expected such incidents to occur and had no intention of having it repaired!