This law-school exam question (and, umm, model answer) is really, really sick. And, sadly, a lot more plausible than most law-school exam questions.
One property question that always seems to pop up concerns "virtually certain" events and the Rule Against Perpetuities. For example, the testamentary disposition "I deed Blackacre to George, except if the Cubs win the World Series to Sammy" is a void clause, because it is not certain that the Cubs will win the World Series within a life in being plus 21 years. Not certain in either the real world or for the lawadmittedly, that congruence is unusual.