Yea, I mean even back in my pre-internet youth there was always someone who had somehow gotten a hold of a porno mag or VHS tape from somewhere. The only thing blocking porn on the internet will do is make kids more resourceful in finding ways to work around those blocks...which I guess might be a good thing.

So installing porn filters and locks on your home computer is probably a good thing, not because it will prevent your kids from watching porn, but it will make them to learn more about computers and computer networks :)