A similar case in Kansas City was reported last year on a Listserv, or electronic mailing list, used by linguistics experts. A University of Kansas linguist said that a waitress friend reported that "fellow workers used to use a name for inner-city families that were known to not leave a tip: Canadians. ‘Hey, we have a table of Canadians.... They're all yours.' "An original reference comes from CincyBlurg on August 27, 2007:
One of my [Black] friends is from the South (that's the Southeastern United States to be precise) and she told me that she had recently discovered that White people had been calling her Canadian.That post also has a pointer to the Racial Slur Database which has much sad yet fascinating information.
She told me a story of when she was working in a shop in the South and she overheard some of her customers complaining that they were always waited on by a Canadian at that place. She didn't understand what they were talking about and assumed they must be talking about someone else.
After this happened several times with different patrons, she mentioned it to one of her coworkers. He told her that 'Canadian' was the new derogatory term that racist Southerners were using to describe persons they would have previously referred to as [N-word]s.
I'm sure I'm not the first person to be reminded of South Park's Bigger Longer & Uncut musical extravaganza "Blame Canada!" by all this, but I haven't run across a specific linkage. The Language Log (a linguistics blog) attributes the reference in part to the sheer incongruity of the notion.
I'm just amazed at people's inventiveness when it comes to ways of being nasty to each other.