They could. They chose not to the last time around. I don't know whether they would make that same decision now. There is also a case in front of the courts right now, because after the last extension, it was clear we had to go to court.
The exclusion is being challenged in Ontario at the moment. That will eventually end up in the Supreme Court of Canada. Even if the government does.... Doing the reference would be faster, but the case will get up to the Supreme Court of Canada. This will be answered eventually.