I knew a lawyer from Buffalo who would substitute “Canadian.” “Look at that bunch of no good Canadians just standing around.” It took me a couple times to figure out what she was saying. When I asked her about it, she said, “Hey, I’m allowed. I’m half Canadian.”
I read an article a long time ago that Canadian was the word used by waiters in restaurants to identify a class of people that didn’t tip very well.
Plenty of references with a Google search.