self-help for copyright owners?

A California congressman is working to fight against the sharing of copyrighted files on the internet by people using peer-to-peer network software. Part of the legislation that he is working on drafting would allow copyright owners to hack into other peoples' computers to locate the presence of copyright protected materials that haven't been purchased. (Copyright owners, or just large multi-media companies?). Between this law, and some of the recent posts on copyfight, I've begun to wonder what types of abuses of privacy and civil libeties will happen in the name of protecting property. I'm not sure that government sanctioned vigilantism is ever a good idea.