An example from Canada is the LMO visa. Employers can essentially sponsor a foreign worker, but only IF they first post a job ad and prove to the government th

An example from Canada is the LMO visa. Employers can essentially sponsor a foreign worker, but only IF they first post a job ad and prove to the government that a Canadian worker can't do it. It's pretty easy to imagine what those job ads look like (a million prerequisites and minimum wage). And subsequently the foreign workers are heavily taken advantage of since they can't switch jobs on that particular visa. Edit - I should add that immigrants put up with it anyway as it gives a path to permanent resident status. The whole visa program erodes the bargaining power of Canadian workers and explains why there's so many jobs advertisements on Canadian job boards with absurdly low pay for the requirements; for example programming jobs that pay $17/hour.