> parents who oppose the ban can easily get around it

Irresponsible parents are irresponsible parents, and they can do much worse than letting their children wander on the Net alone. IFAIK no law at least here forbids parents from giving alcohol or tobacco to their children, even though it is forbidden to sell those products to them. Toxic social media are mostly the same.

Although the topic is a ban, I think the idea is less about forbidding and punishing, and more about helping - albeit in questionably manner according to some - helping parents with "regulating" the access of their children to the Net. Of course, the easy answer is to recommend giving them dumb phones instead of smartphones, but really a smartphone is too useful to be ignored around high-school age.