> A more technically sound approach would be content controls directly implemented on the devices parents chose to give their children Passive aggression level 10, and I approve.
This is the only true solution. Parents need to take responsibility for what their kids are doing online, what they’re viewing and who they’re talking to. This generation of parents should be prepared for that but apparently not.
But we're in an era now where cell phones and tablets — especially used + low-spec ones — are something that even a young child can acquire en masse: from their friends at school, or from any mall kiosk or convenience store with their allowance, etc.
You can put all the parental controls you like on the nice phone you buy your child — but how do you put parental controls on the four other phones you have no idea they own?
(Before you say "search their room" — they could leave them in their desk at school, charging them with a battery bank they charged at home or got a friend to charge for them; and then use them with free public wi-fi rather than locked-down school wi-fi. This doesn't require any particular cleverness; it's the path of least resistance!)
If you ask me "well, what do we do, then?"... I have no idea, honestly.