Comment by Kerb_

I dunno about "most places". I definitely had to get a boating license, though for some reason the law had an exception for people born before 1978. A cursory search show most states have some sort of legislation regarding it. Many other countries have different legislation based on engine horsepower and age, but it's definitely regulated to some degree most places I've seen. I don't suppose you'd be able to paddle hard enough to cause serious damage