Is a contract void for uncertainty, void for uncertain uncertainty or void for unjust enrichment?

The defendants submit that even if the contract was void for uncertainty, the plaintiffs’ claims for unjust enrichment would fail because they cannot invoke equitable remedies when they do not come with “clean hands.” That is, the defendants say the plaintiffs have voluntarily obtained the services offered by the defendants, without full and proper payment of the parking fees, or as described in Imperial Parking v. Canada, they are failed “gamblers.” In this regard, Robertson J.A. makes the following comments at para. 16: … In any event, the person who parks in one of the appellant's lots and intentionally does not purchase a ticket cannot invoke equity to come to his or her aid because of the “clean hands” requirement.