The only thing is that when they do come to a port of entry, they then are recorded as to whether they have proper documentation—a student visa, a worker visa, or a visitor visa—or whether they are a permanent resident with all the requisite documentation. If they simply come in here.... Don't forget, the last step in the whole process of obtaining the worker permit is that your employer already has been approved in Canada to qualify to hire a foreign worker.
In Manitoba, (a) they're registered with the Province of Manitoba, and (b) they go through the whole list of advertising for workers in that field who have certain skills. They have to do it online in the Job Bank. They have to provide a list of all the people who have applied for that job in Canada and have been turned down for one reason or another. Only then does Service Canada permit the employer to offer employment to a foreign worker overseas, who, with his or her application, applies and comes to Canada.
It's a long process.