Read the article on the STM site. Lots of good stuff there. Kirkin of the Tartans was a way to raise money and awareness for British war relief efforts in WWII. The first was likely in 1941. A worthy cause, even if the "myth" was made up to market it better.

So as long as no one is trying to make it into a Scottish thing, but merely a Canadian and American expression of solidarity with the people of Scotland, no harm, no foul.