I would absolutely support that position if it were compatible with observable reality. My family and school failed to stop me getting my hands on booze, fags,

I would absolutely support that position if it were compatible with observable reality. My family and school failed to stop me getting my hands on booze, fags, drugs, and porn. Teenagers are fundamentally not controllable. The Amish and the Mormons are having some success, but that's likely not what libertarians want to hear. What you describe is the status quo. Parents and schools are already, variously, giving The Talk, confiscating devices, enabling internet filters. Society deems these measures ineffective. In tiny part, that's a skill issue, but mostly it's just trying to cut down a tree with a herring. Again: teenagers. You may, of course, sulk about age restrictions on alcohol. Prohibitionists would like that. Keep your out of the contested zone, make them look reasonable. If you want to stand on your principles, try seasteading. But I'd appreciate coherent contributions to the debate, to offset the excesses of the pearl-clutchers and the spies.