Cor, if people started doing that in my city, forget about kids going out to have fun, school attendance would drop like a stone on account of it becoming de facto illegal for you to let your kids transport themselves to school.

That sounds more to me like a thing that happens in the suburbs, where kids need to be chauffeured around in cars everywhere and the streets are too fast and too packed with cars for bikes to be safe, so parents don't even get the opportunity to contemplate letting their kids out of their sight.