Years ago at a previous job working in construction, I heard one of the supervisors saying "he's trouble" a lot. It wasn't any code words or anything, just some white dudes thinking I was troublemaker or something. I ignored them because I really needed the job at the time, and I didn't want to get into it with them.
Anyway, I can't say I've heard most of the words/codewords/phrases from previous jobs, but I'm sure there's something I missed back in those days and didn't pay attention to.
I've heard calling a black person Canadian, was a racist code word as well?
I can't say I've heard of that one before. Doesn't make much sense to me since the majority of Canada is like the US, mostly white.