I would say a couple of things.
There are different models, and one of the benefits of being so far behind the curve here in Canada is that we can learn from international best practices.
Certainly you see different models around the world. Some countries, such as France, have a legislated, graduated response. That is in New Zealand and Korea and elsewhere. Others, like many European countries, have a provision in their legislation that brings ISPs and rights holders to the table by saying that if you want the benefit of a safe harbour, you need to have an effective policy to deal with repeat infringers who use your network.
If all you're doing is sending notices, it's just notice after notice after notice. It's like saying, “Stop, or I'll tell you to stop again”. You need to have escalating deterrent measures that people will take seriously to change their behaviour, because that is the objective of any sort of program. It's to get people to change their behaviour, which they're not going to do if all they get is a notice.