It is up to a defendant to determine what arguments they want to raise before a court. It's difficult to estimate the number of people, or other types of individuals, who may wish to raise this, but I can tell you that on its plain meaning it appears to be a clause intended to be used in exceptional circumstances.
Evidence of meeting #12 for Environment and Sustainable Development in the 40th Parliament, 2nd session. (The original version is on Parliament’s site, as are the minutes.) The winning word was court.
A recording is available from Parliament.