Earlier quoted context omitted.
> How would network restrictions help, there is WiFi at friends houses / everywhere. > > If you don't want your kids to connect to things then don't let your kids have devices that connect to things.
Comment said the restrictions belong on the network being connected to, which is useless when you can connect else where. Yes not giving your kids access to a device is one option; parental controls are another. I'm not sure either will work entirely, but that's another point.
And locking down the primary device a kid has access to creates the lure of the forbidden; that won't last any longer than their access to another device without those restrictions. That also creates an environment where if they do find something they really ought to be able to talk an adult about, they can't talk to a parent about it because they'll be in trouble (and get their friends in trouble).
One of the widely studied aspects of child psychology is how to instill guidelines that last even when they're elsewhere without any enforcement other than self-enforcement.