Crazy Idea #3 - Alternatives to High School

What if the energy and idealism of teens who aren't engaged at school could be directed constructively? Starting at age 14 teens must demonstrate sustained effort in their studies to stay in school. Without it, they will be given other options, such as military training, technical apprenticeships, tree planting, child care, work in a food bank, community service or ??. There would be no option to just hang around. Free public high school education would be available for all youth until age 30, with the stipulation that they maintain sustained effort in their studies.