One of the former chairs of this committee found herself quite ill on a plane, and the plane landed in Texas to get her to a hospital quickly. It isn't unknown, when people are sick with something unknown to them, for planes to do that, as well.
What I'm failing to see is the difference between land transport and sea or air. To me, this reduces the requirement and saves money but might put Canadians' health at risk. In other words, you're saying that there are very strict rules to be applied to people who travel by sea or air, but if they travel by land, you're hoping that common sense will prevail.