Iporcano .. I work around teens, and in and out of high schools. You really have not idea what you are talking about. Sorry.
"Society has no business second guessing motivations." Really? So, if she wants to go become a hooker for her next school paper, that is ok?
Society has every right to control certain behavior. Drinking? Age restriction.
Smoking? Drug use? In most states, a 14 year old can not work in many jobs because of age. Bars? Dangerous machinery. We don't allow 14 year olds to vote. A 14 year old can not run for office, sign contracts, borrow money. A 14 year old can not drive an automobile.
But you think it is ok for this kid to take a boat around the world?
Please, I realize you are trying to be a devil's advocate, but do not make a total fool of yourself in the process.