Jay,

Of the kirkin's I've been to, both outdoors, representatives of the clans at the games carry a tartan banner (flag) and are gathered in a certain spot. At Grandfather, I think they were all lined up in front of the clergyman. A blessing of the tartan is read aloud. Sometimes the tartans are declared by name. I don't think someone could just walk up and add their non-clan tartan to the line-up.

I'll be there both days with the Barclay clan. It's be nice to meet you.