Wow! Obviously this is a touchy subject. I think here in America the Scottish and Irish traditions have become mixed as "Celtic" (leaving out all those Celts on the Continent, of course.) However, in many places around the world, "American"" is associated with cowboy hats and boots, so misinformation can go both ways.

One of the joys of wearing a kilt is that people will feel free to come up and ask "why are you wearing a kilt on St Paddy's Day," which gives all of us an opening to try to educate the hoi polloi in a fun, non-threatening way. Who knows, it might even stick!