New Zealand recently passed a law (which the US government asked for, according to a Wikileaks cable, and the government here rolled over for them) which create

New Zealand recently passed a law (which the US government asked for, according to a Wikileaks cable, and the government here rolled over for them) which creates civil penalties for being an 'account holder' with an 'Internet Protocol Address Provider' if the IP address is found to have downloaded copyrighted material. So when the law comes into force in New Zealand, there will be no need to prove who 'used the Internet' - only who the account holder was for a given IP address, and that the IP address was involved in transferring material owned by the plaintiff (and even then, not really prove - having sent a notice to the defendant via their ISP creates an assumption of liability that has to be disproved by the defendant).