Judge Birss has issued a ruling in the Patents County Court which effectively makes the DEA copyright rules unworkable when based on an IP address:
In a ruling in the Patents county court, Birss asked: "Does the process of identifying an IP address in this way establish that any infringement of copyright has taken place by anyone related to that IP address at all?"Birss doesn't say that it can't be proved, but that there is no case law which means the owner of a connection can automatically be held responsible for all the activity on that connection. That, though, should be enough to make anyone think twice before embarking on action - any legal adventure is likely to be long, drawn-out, expensive and lacking any certainty of success.
He said that the assertion did not hold up: "Even if it is proof of infringement by somebody, merely identifying that an IP address has been involved with infringement [does not make it] clear to me that the person identified must be infringing one way or another. The fact that someone may have infringed does not mean the particular named defendant has done so."