AFAIK it's always been one of the bigger gray areas regarding pirating copyrighted material. From what I've read it's still a "we have no formal proof that people are prosecuted based on it, but we also have no proof that they aren't/can't be".
It is from 2008 though, things have changed. Just today a domain was seized by the UK govt on grounds of copyright infringement just because it was running a proxy. In Austria someone was convicted for running a Tor exit node about a month ago.
Also, read https://www.schneier.com/blog/archives/2008/01/my_open_wirel... as linked below in this thread.