They would pay a small fee to a Canada company? and wouldn’t pay the American Western Union a fee for sending their money to Mexico?
Both Western Union and the company in Canada would take a cut.
To make it more simple, Julio in San Antonio wants to send cash to his mother in Monterrey. He has a cousin in Calgary and sends money to his cousin and the cousin sends the money to Monterrey.
You are not going to be able to stop that.