Hugh

Your point does not lessen the fact that the owners of home wifi networks have an obligation under VM's AUP to at least to attempt to secure their links - if there had been a "brute force" attempt to hack the router, this would show up on the firewall logs, surely, which would mitigate any possible proceedings. If the subscriber could provide this evidence, there would be no case. The plaintiff would have provided evidence (IP logs and time), and the defendant would have to counter that (besides saying "it wasn't me, guv").

In a civil case, the BPI would provide evidence to show that a machine/network had been used to download copyrighted music without permission - it would then be up to the owner of that network/machine to show otherwise (by use of network logs, etc); and remember, the difference between a criminal case and a civil case is that in a civil case, the plaintiff must simply convince the court or tribunal that their claim is valid, and that on balance of probability it is likely that the defendant is guilty. There is a big difference between criminal proceedings (fraud and child porn) and civil (copyright violation).