It happens with visa officers.
This is the spousal sponsorship class or the family reunification class. We know that fraud is an ongoing concern overall. The incident rates are low, but it happens. Visa officers, who are the decision-makers on those files—it's a delegated authority from the minister in the legislative framework—have specific training to detect if this might be a case of marriage fraud.
How they do that is a bit science and art. A lot of this is their own experience in looking at files. When you work with visa officers and you see them going through immigration files, they can detect patterns. If they suspect that this might be a fraudulent relationship, they ask more questions. They ask for more documents. They'll talk with enforcement agencies, such as the Canada Border Services Agency, and they could choose to bring the applicant in for a face-to-face interview to ask further questions.