One of the common comments about getting the kids out of karts and into cars is that we don't have something that piques their interest. F1000 WILL. Make them wait too long and they'll be on to something else.
Sure there is a level of better judgement that comes with experience and maturity, but some of these kids have more experience than many of us. Even if they've only been karting for 8 years, the number of races they have competed in and the level of competition for the serious karter is greater than what most of us will be exposed to in 20 years of racing.
Agreed, they will likely make a bad choice once in a while, as will most 16 or 18 year olds. Problem is that they probably won't be paying as much for their mistake financially or physically as the rest of us. So, what do you do--tell them they must have a job to report to on Monday as well as kids to raise before they can play with us?
Further, a 14 year old that has a Mommy or Daddy willing AND able to fund a f1000 effort didn't just step out of a 50 mph kart.
But, I do get your point. The lessons to be learned early in your career will hurt you and everyone else more than a broken collar bone and a bent up $8000 kart.