When I was in university, there were a whole bunch of people who "gooned" and failed exams. Most were from conservative families and were not given any internet access whatsoever. They never built the "antibodies" for the wild wild web.

I do restrict my kids' phone access, but often it's with discussion. I tell them I'm shutting down their phone access. Usually when they don't do their homework or when they start getting emotional. They'll build the self control muscle. And when they find the hard stuff, they'll be a little more prepared.