being overly experimental generally makes one look foolish among people who know how to wear a kilt
That is a very interesting point and makes me wonder that since what is generally accepted as right and proper is made so primarily because it's been done that way for so long, at what point does something new and unique gain the same acceptance. From most of the comments thus far I can gather that the "rules" are more a genre of popular habits. Habits that have over the years become so engrained that when someone decides to make new habits they are quickly labelled as breaking with tradition, or disrespecting heritage etc. I would argue that every tradition likely started out with quite a stir to the accepted norms of the time, and that it only became a tradition once enough people copied it. In my honest opinion proper highland dress is a product of invention and not evolution and in being so becomes subject to all those unwritten, and unverifiable rules.

The things that make good presentation are hard to argue against, and in themselves leave a massive margin for individual expression. What causes my raised eyebrow is when things get to a formal level and suddenly the "rules" appear. Call it my natural aversion to authority but when someone tells me that certain things are musts, and others are must nots I feel the need to understand why. So far the answer, if you distill it down to it's essence has simply been out of habit. I can accept that. But along with this I also accept that any habit can be changed, and that there is always room for new traditions to be born as long as they are created with respect.