I have NO problems with requiring minors adult supervision. We have several youth programs around here - the ALWAYS have adults in powerboats around... i see no problem with that.
From what I understand regarding the adult supervision, the intent is to require the adult to be IN THE SAME VESSEL as the minor operator.
This kind of pokes youth sailing in the eye. So the 17 year old pair of sailors in an F-18 would have to be supervised by an adult.
I haven't observed that much "showing off" by yoots on sailboats. It's not exactly like they're hauling butt in a powerboat or (worse) jet-ski...