If ever you can be legally punished not because you did something that hurt or even endangered someone, but simply because you didn't ask permission first, liberty has one foot already in the grave.
If someone with a license to do X does X and hurts or endangers somebody anyway despite their license, they get rightly punished for it anyway.
If somebody with a license to do X does X and nobody gets hurt or endangered in any way, they don't get in trouble for anything, as they shouldn't.
If somebody without a license to do X does X and hurts or endangers somebody, they get rightly punished for it too.
But if somebody without a license to do X does X and nobody gets hurt or endangered in any way, they get punished, not for causing any harm or danger, but for having the gall not to ask permission before safely and harmlessly doing something.
The only difference mandatory licensure ever makes is punishing people who wouldn't have been punished otherwise because they weren't doing anything harmful or dangerous. Mandatory licensure, of anything, only ever harms innocents, by punishing them for harmless behavior that they simply didn't ask permission for first.