Wearing kilts of other tartans than your clans.

[Swampthing]

I tried to ask permission from the Clan Chattan association to wear MacQueen, but they told me there was nobody with any MacQueen authority to ask.

Because there isn't. They don't mind if you wear it.

My new metaphor for tartans: team colors.
Let's say we have two universities, USON and MCU.
And I'll just call them University of South Ontario and Mary's Catholic University, respectively. Now USON's team colors are brown and orange, like Autumn or something; MCU's colors are gold and purple.
If you go to MCU, and you are kind of enthusiastic, you are like a MacLeod that cares about his clan, if not then you are like a MacLeod who probably doesn't even know about his heritage. So, let's go with the former, you wear some gold and purple because those are the official colors of the university, and it's team. If your not at an event related to the university/team, would it be wrong to wear any other color?
Or simply would it be wrong to wear any other color? Would the guys at USON get mad if you wore orange and brown? Would they even have a justified reason? See? It's no different with Clans and their tartans, those tartans are simply tartans that their chieftain or whoever chose as their official tartan(s);
Just like team colors being the official colors of the team and/or university.
Although I guess teams usually aren't just college sports. ;)