As far as enforcement of the rules is concerned, some foreign workers already arrived in Quebec this past Saturday. The entrepreneurs or businesses do not yet have all the information on the rules they will have to follow or on who will be enforcing them. Whistleblowing aside, what's important here, of course, is protecting the foreign workers who arrive, but it is also about protecting the entire population in the regions where they will go to work.
On April 14th, 2020. See this statement in context.