I know that apparently, some American travelers put Canadian flags on their luggage or carry on then claiming they’re from Canada (the dead giveaway on debunking this is their passport, since how can you be “Canadian” when you have US citizenship unless you’re a dual citizen in possession of both nationalities) since some of them have hatred towards the US or feel ashamed of the country due to its internal affairs.
Yes. I did it. Mainly in response to invasive questions from dodgy people. I had a fake name, a back story about where my family lived, etc.
After 9/11 and then the global war of terror, it was a prudent thing to have on dial. Never wrote clothes or put Canadian stuff on my bags.