I can't argue with anything said so far. In particular I agree that some things seem like a good idea at the time, but evolve into something else.

Still, what I notice again and again is the lengths we will go to to claim a tartan (or other affiliation) as our own when we want to. You can read here and elsewhere that clan affiliation only passes through the paternal line, only through the maternal line, through either or both, or can be adopted by any interested person. If all of those things are true, they are "true" to different people, which I imagine is the case. I will probably never be a clan chief, but if I were, I am not so sure how I would react to the practice, much discussed here, of asking permission to wear my clan tartan. Somehow, I am put in mind of some Monty Python skit, where John Cleese is trying to get something done, say a war or distilling a particularly intricate batch of whisky, and people keep coming up to him and asking about wearing his tartan. HOW SHALL WE ____ OFF, MASTER? OK, that was Graham Chapman, but you get my point. Call it respect, call it admiration, call it social affiliation...

Wait, let me put it this way. Let's say your name is Campbell. You are riding down the highway and you see an attractive woman with a Clan Campbell sticker on her car, pulled over with a flat tire. Do you suppose your wife is going to believe the Campbell sticker is why you stopped? Would you still stop if there were two lazy looking louts instead of the winsome lass? Would you leave work, home, and family and travel to Scotland if Torquil Campbell sent you a letter asking you to come at your own expense and help him "Do something about these McDonalds once and for all?" What if the letter were pre-printed and said "Dear friend or member of Clan Campbell"? What if it were a postcard?

My point is this: we can often manufacture a family connection when we want one. We may even attend Clan gatherings. We may send in dues. But for most of us, the Clan tartan is 99% spiritual and 1% practical at most. If it offends your spirituality, stay away. If it doesn't, have a good time.