To be even fairer, the ISPs and AFACT already have a procedure in place to do this. AFACT agreed to it and choose to blissfully ignore it in favour of asking the ISP to illegally do their dirty work.
AFACT can stop abusing the legal system and fuck off. They have a procedure that allows them to inform an ISP of an infringement via a magistrate, the ISP will happily comply with the request and send the agreed details to the respective law enforcement agency. The fact that AFACT have sent 0 of these requests since they were introduced almost 10 years ago proves they really don't give a shit about the ISP, or due process.
An ISP is NOT a judicial body. Infringement Notices are not legal documents and AFACT is not Law Enforcement.