GAARs are in place in many other statutes in Canada, starting with the most important one, which is the Income Tax Act of Canada. Those types of rules have been used effectively to do exactly what you are looking to do, which is avoid the ability for individuals to design legal mechanisms to avoid taxation.
Now, avoiding taxation and delaying taxation are two very different things. In this particular case, if someone is creating a construct that would allow them to advance a private interest, I think this goes back to the question from Mr. Thériault. It's an ethical question, not a legal one. It would be interesting to see what that rule looked like. I would certainly be happy to comment on a rule once it's been designed, but a general anti-avoidance rule in this area undermines the whole purpose of the act. Anyone who's willing to design that kind of tool to avoid the application of the act is going to find another way around it.