what about parents who cruise with kids who don't participate in these programs? Mine is 12 and he refuses to go to kid's club. If we use your logic, we will be unable to sail because the cruise will be "sold" out to anyone with kids within minutes of opening up, even if we don't use the kid's club.
Plus, 17 yo teens aren't supervised in the kid's club anyway. So, what program will be handling them?
So, in this case I say - if you want a cruise with no more than 100 kids, don't try to turn an RCI ship into them. Go try something else which already caters to your interests.