"unwitting facilitators of infringement " - this sort of logic would make Australia Post complicit in kidnapping because the kidnappers sent their demand by mail.
Indeed, but they should also drag the power companies in for infringers who are not running off-the-grid, after all, computers do not run without electricity.
Also the company that maintains the infrastructure between their ISP and the house, after all, if that didn't exist the person couldn't possibly have infringed…
In fact, let's have the copyright holders sue the ACMA since they manage the licensing of said infrastructure.
It'll look like the US legal system in no time!