The North West Mounted Police, later to become the RCMP, arrived in southern Alberta where American traders were operating along the United States border. A goal of the newly formed force was to stop the illicit trade of whiskey for fur and buffalo robes. The newly formed police force started to destroy some of that whiskey, which was transported in large metal cans.
Source: The North-West Mounted Police: Policing the West (n. d.). 21st Century Learning.