Should use IP address instead.
Except all they have to do is have a dynamic IP vs. Static. All they have to do is use a library computer. All they have to do is hijack someone else’s WiFi...
It’s not enforceable as a preventative measure. The best you could do is essentially make it an add-on charge when they are already caught. That would be OK by me, but I sincerely doubt that such a law would keep many pedophiles off of MySpace.
Frankly I think the real solution is much tougher penalties for convicted pedophiles and an elimination of the idea that they can be “cured”.