[stephenr]

Unless you also block outgoing DNS requests on the router, this seems like a 10 minute (before being defeated) solution at best.

A search for "get around opendns content blocked" returns instant, step-through guides to change your browser/OS DNS settings.

[saturdayplace]

I assume that someone who's configuring their router will also be configuring their children's devices in such a way that the children won't have permissions to make those changes.