Here is a commentary on the change to the copyright act, section 92A, and the #blackout protest. Its by my father, Glen Wiggs, who is a lawyer and ex-head of the Advertising Standards Authority, a self-regulating organisation here in NZ. Dad is currently the Adjunct Professor of Advertising Regulation at Sunshine University, and an expert on industry self-regulation.
The key issue is that it amounts to conviction without trial. In the event of an ISP terminating then if challenged in court it would need to prove that the principles of natural justice were followed. In other words a fair trial. The law is draconian but it is incumbent on the ISPs to establish procedures that are fair and include the right to be heard.
Therefore if a third person did the downloading then this would need to be taken into account by the ISP.
Yes try and change the law but this is likely to take years. The quicker route is to press the ISPs to set up a fair system where all parties have the right to be heard and the decision is made by an independent person/tribunal.
If you compare it with advertising. It is common for complainants, including politicians, to demand that an ad be withdrawn immediately. This would be conviction without trial therefore the ASA was established.
Carry on the protest but you may be perceived as defending law-breakers. However you will get public backing for a fair trial. There is no need for the law to be changed to achieve this objective as it can be done by self-regulation