Questionable services???
I get all my linux distro's using torrents, also ID releases all linux server binaries through torrent these days.
It is not a questionable service, it is a perfectly legitimate service that the record labels are trying to spin as questionable.
As for the proxy thing, who said it had to be a free anon proxy? If people who are downloading dodgy stuff really are looking to protect themselves they could quite happily pay for a service based in say China, Russia, etc Would be perfectly legal and the record labels will have problems getting the information out of those countries.
The not so legal route, hackers with botnets selling off the ability to proxy through compromised machines (which will only lead to innocent people getting accused of downloading stuff)
It's like trying to scan brainwaves to see if somebody is thinking the wrong thing...