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.
Traveled Europe in the 90’s with a backpack. It was pretty common then. I met loads of Americans claiming to be Canadian. As a travelled Canadian myself it was fairly obvious to me but some insisted it was worthwhile. It certainly fell off over the years I traveled however.