trademark application serve as a screening mechanism for ensuring only eligible and owned marks are registered. A registered mark effectively creates a presumption that the mark is distinctive, valid and owned by the registered owner. Post-registration proceedings to have registration expunged are available under section 57 and 18 of the Act. Justification for protection against passing off The purpose of the tort and statutory protection against passing off is twofold: first, it protects the plaintiffs' proprietary rights in the goodwill of their business; and second, it protects the public interest in ensuring that consumers are not misled as to the source of goods or services. In this respect, passing off encroaches on both competition law and consumer protection law. Professor David Vaver suggests generally that "[t]he basic theory of the tort is to prevent the disruption of economic relations by deliberate or innocent misrepresentations that deceive or confuse consumers in their marketplace decisions." Vaver also notes the centrality and complementarity of both purposes in the tort of passing off and trade-mark law: The role of passing-off is therefore to rectify the likely harms one trader suffers from the acts of another that mistakenly deflect consumers from dealing with the former or his products or services. Although the tort grew up to protect the interests of traders rather than consumers, the less it works to prevent consumer confusion, the more it becomes merely a law protecting traders from unfair competition. That goal may be what other torts, such as conspiracy or unlawful interference with economic relations, and Competition Act provisions regulating false and misleading advertising practices aim at. Passing-off need not replicate their aspirations. Protection against competition In Ciba-Geigy the Supreme Court of Canada explained the purpose of the law. In exploring the function of passing off as an action against competition, the Court cited Salmond on Torts with endorsement: [t]he courts have wavered between two conceptions of a passing off action — as a remedy for the invasion of a quasi-proprietary right in a trade name or trade mark, and as a remedy, analogous to the action on the case for deceit, for invasion of the personal right not to be injured by fraudulent competition. The true basis of the action is that the passing off injures the right of property in the plaintiff, that right of property being his right to the goodwill of his business. The Court went