If my opinion counts, the only way to ever resolve any Legal issues would be to make this sport 18+ only.
18 to buy AND to play. Period, no loopholes.
Yes, the under 18 will scream at me for it. But read again; to solve ANY legal problems, that's the only way. Fair? Laws dont consider fairness or maturity, only liability.
It would also go a long way to solving the public's distorted views and lawmaker's ideas if you had to be of legal age.
But this wont get solved any time soon.