Phil brings up an important point, and that is that different people mean different things by the word "traditional." A lot of times those ideas are compatible, but not always.

In my experience discussing Highland dress with various people, I have found two concepts of "traditional" to be prominant.

The first simply means "what I recall my grandfather wearing" (or some variation thereof). In other words, what are the prevelant styles considered "proper" within living memory?

The second view would equate "traditional" to "historic." If there is a record of it being commonly done in the past, it is traditional.

To illustrate how these viewpoints can yield differing results, consider the choice between a 4 yard box pleated kilt, or an 8 yard knife pleated kilt. I am helping someone purchase their first kilt, and they are trying to decide between these two styles. They ask me, "Which is more traditional?" What do I say?

Well, the four yard box pleated kilt was the original style of tailored kilt, from the end of the eighteenth century through to the mid-nineteenth. However, since the end of the nineteenth century, the eight yard knife pleated kilt has been the most common style worn, and is what most people think of as a "kilt" today.

Having read Rathdown's original post, he would likely consider the box pleated kilt to be "historic" and the knife pleated "traditional," and that's a very valid viewpoint. But someone else may consider the box pleated more traditional because it is older, or because it was the original style of pleating, etc.

I would argue that they are both traditional, but that we need to be aware that different people have different concepts of just what is meant by that term.