When CRA believes a taxpayer has acted with gross negligence, they assess a penalty that amounts to 50% of the tax reassessed.
If CRA suspects someone (such as an accountant, financial planner or board member) has assisted someone else in evading tax, they have the power to assess the advisor third-party penalties, which can be astronomical.
These assessments are extremely subjective. A vigorous defence can lead to a positive outcome for the taxpayer.