window of opportunity for opponents to file a statement of opposition to the proposed registration. Section 38 of the Act requires opponents to provide detailed specifications of the grounds for opposition, such that the applicant has a fair opportunity to rebut the allegations and meet their onus of satisfying the registrar that registration is warranted. Oppositions to proposed registration Subsection 38(2) provides an opponent with seven grounds on which to base a statement of opposition, which can generally be categorized under the following areas: noncompliance with filing requirements, mark unregistrable (see section 12), applicant is not the owner or the mark lacks distinctiveness. Once the statement of opposition is filed, the proceedings are determined by the Trademarks Opposition Board. Decisions of the Board can be appealed to the Federal Court of Canada. Differences between registered and unregistered marks Registration is costly; however, once the trademark is registered, proving an infringement is easier and therefore possibly less expensive than a common law passing-off action. The rationales behind the two notions also differ: passing off merely protects the disruption of economic relations by misrepresentation, while registration actually sees marks as commodities. Other differences exist: Unlike passing off, registration doesn't require market reputation, although it does require actual use. Registration covers Canada as a whole, while passing off is merely local. Registration doesn't require proof of damage. It can also allow a claimant to stop the use of similar marks, despite the defendant's disavowal. In passing-off, however, the mark can be used by similar businesses as long as it doesn't lead to confusion. Moreover, disavowal and honesty are taken into account. Passing-off requires proof of the existence of reputation each time and action is brought, whereas registration gives a presumption of validity and gives continuous protection against passing-off and infringement in case of normal use of the mark. Misrepresentation is required in passing-off, which doesn't protect loss of control for instance, while mere depreciation of goodwill could suffice in registration. However, this distinction is more limited nowadays, since passing off gives protection against loss of control as long as misrepresentation is proved. Relying on the common law action of passing off is still useful when a symbol cannot be registered or when registration is invalid. Moreover, its flexibility makes it more adequate than the concept of infringement provided by the Act for situations that are not covered by the legislation, for instance misleading