tamer.willson wrote

I think you all are looking at a wrong angle, imagine a great firewall cannot block VPN completely from state level, how do you expect a private company like trend micro to do it????
Wake up people, mind if I suggest easier and more realistic solution to the problem:
1, cut off your kid's allowance as I know most of the VPN are not free.
2, beat the crap out of your children, so they would quite messing around.

@hansremmerswaa ITs three years now and looks like keyword filtering has not been added yet. 

Any update on this issue?

Parental controls shouldn't just exist on your network hardware, you should also lock down their devices. Computers should have administrator accounts and children should be using resricted accounts that prevent the installation of software without you allowing it. Same thing goes with mobiles, although it is probably more difficult to implement.

Failing that, you should talk to your kid and let them know you can see they are using a VPN. Them knowing you know may be enough to stop them, but if not, just take the phone off them as a consequence. I assume you're the one paying the bills, afterall.