Quote Originally Posted by davidlpope View Post
It seems to me that you're overthinking this. If you believe that one of the results of this marriage is that your future son-in-law becomes part of your family, and if he doesn't already have a tartan "of his own", then it makes sense for him to wear the tartan that the rest of your family does.

If you are concerned, though, about the propriety of it, then the correct person to inquire with is your clan chief. He or she (IMO) is the sole arbiter of who may wear their tartan, if they are inclined to exercise that right. I suspect that most chiefs, though, are busy with more pressing things.
Precisely. Well said, David.