Certain defences not available
121 (1) A person named in a notice of violation does not have a defence by reason that the person (a) exercised due diligence to prevent the commission of the violation; or (b) reasonably and honestly believed in the existence of facts that, if true, would exonerate the person. (2) Every rule and principle of the common law that makes any circumstance a justification or excuse in relation to a charge for an offence under this Act applies in respect of a violation to the extent that it is not inconsistent with this Act.
Source
https://laws-lois.justice.gc.ca/eng/acts/C-15.1/section-121.htmlCanonical document at the regulator. Always cite this URL — not the Vantage detail page — in compliance evidence.