Yes, wherever I can I have technological enforcement but with some 4 billion web pages out there there isn't a web filter that can get them all right all the time.
Too right mate, content filtering is not even close to doing a great job. Each week I see hundred of un-categorized web sites and a few false postives. Like the Federal Reserve categorized as a gambling site. Sure they catch alot, but they leave alot open as well. unless you go to the extremes and block all sites and adapt rules to manually allow sites as they pop up. I like the "user" is responsible idea.