This is neither here nor there, and it's never happened to me since, but this is an experience I had years ago. I have always thought was odd to this day.
I was getting married (the first time) and for our invitations, I wanted to scan a piece of my tartan fabric to use as a background. I was at a printing shop called Kinkos, high quality scanners weren't a dime a dozen in those days. The clerk there said they wouldn't scan and print it because he thought it would be copyrighted and I needed written permission to use the "pattern." Joking, I asked who I would need to get permission from, the clan chieftain? Completely straight faced He said "yes that would work". I ended up going somewhere else and had no trouble.
Has anyone else ever heard of anything like this happening? I guess I had never thought about copyright issues with tartans.