Bottom line is that you wear what you want However you can take this example for an answer to your question. My mom was a Hall. Hall is a sept of Skene. I wear Skene by right. From her mom's side comes Williams. I wear Gunn by right. My dad's mom was a Shephard. I wear that by right. Very closely realted is Brown. I wear that by right.

I also wear Royal Stewart. Hunting Stewart, Buchannan, Black Watch, Gordon & anything esle I wish because I want to. I do not wear U.S.A. military tartans because of personal family reasons. We have a long history as a family for military service & I never served. Others that have never served DO wear them out of respect. Let no one tell you that you are forbidded to wear a perticular tartan.