Judging on the basis of the state of his elbows, knees and knuckles, he's mighty skilled at skateboarding. Wearing too much protective equipment might hamper some of his well-practised tricks.
However, he's not yet managed to persuade me of that, it appears, since I've insisted so far on him wearing protection. I've promised him a spanking, so a spanking he will get - sufficient to ensure he's really felt it.
I will not confiscate his skateboard since I suspect that, if I do, he'll have no difficulty borrowing the use of one from his fellow skateboarders. Once he's recovered from his spanking, we'll start negotiating. My red line will be the use of effective head protection. Beyond that, if he is persuasive enough, I'll concede that he may wear elastic knee and elbow supports rather than padded ones - and for his knuckles the (field) hockey knuckle protectors that do not impair grip. In return for my agreement along these lines, he will have to agree that if I catch him again skateboarding without that lesser level of protection, he will undergo a short back and sides haircut - surely damaging his street-cred with his skateboarding mates!
I hope the threat of that will be more effective than any threats to his bottom.