weeks - 9:42 pm on Jun 9, 2010 (gmt 0)
Having obtained the IP addresses, they will immediately argue that an IP address uniquely and infallibly identifies a specific person (who is the ISP's customer.)
If their case depends on this, they are in trouble. I do wish we could enforce copyright in a reasonable way. This, alas, is not reasonable.
But, keep in mind that if no one made any kind of money on the copy or benefited in anyway, it's difficult to sue for copyright infringement.