I'll try to be very brief, even though it's very complex. An employer who wants to bring in a live-in caregiver from outside Canada must absolutely first do business with Human Resources Canada to have the employment offer validated. That's where the actions of the recruitment agencies are very difficult and bizarre.
The employer receives the authorization to bring in someone to Canada so as not to penalize the landed immigrants already here. CIC issues a work permit stating the name and address of that employer. Everything is recorded. If a live-in caregiver arrives in Canada as a result of a fictitious employer, that means that something was very poorly done at the outset by Human Resources Canada, the agency or a third person. Those three stakeholders are required to work together, in addition to Immigration Québec, of course.