In Australia the court ruled that they can only sue for the cost of renting the movie, so they don't bother trying to recoup their ten bucks
Canada is capped at $5k for noncommercial infringement, and even at that amount it still isn't worth it for the copyright holder to go to court.
That's interesting. Do you have further reading? I've seen AFACT v iiNet, but that doesn't look to be the source of "cost of renting", just that the ISP isn't responsible for their users.