Curious about the "rules"

[kiltedwolfman]

Some very good posts so far, and I give thanks to those who have posted. I am not asking these things for myself as I do have a habit of dressing decently ( at least to me I do hehe )
I am thinking of times when I've heard; or read, that on this type of occasion, or that type of occasion one MUST wear this, or obversely one MUST NOT wear that. And again that makes me beg the question why? Or why not? For example on another thread there is discussion about wearing a dirk. Many replies have stated quite certainly that there are times is must not be worn, and there are times it is acceptable. The same is said about fly plaids, or miniature medals etc. Why do these rules, guidelines, whatever you would call them exist? Is a person sporting a nice well turned out casual set completely out of sorts is he wears a dirk? Ifso why? Or is a person under dressed if they attend a white tie affair and neglect a fly plaid or his/her miniatures? Again ifso why?
It appears to me so far that many ideas on what should be worn and when are a matter of past precedent and insomuch are maintained by the simplest of justifications, it's just the way it's always been done.
I wonder if it isn't time for an onverhaul on convention? Or perhaps an upgrade of the apparatus so to speak since when you look at some highland fashion it often looks like something pulled from antiquity.

* Disclaimer* I thank everyone for their patience, and thoughtful responces. My goal is active and quality discussion, as well as clarification. There are many a newcomer that certainly enjoy a decent exchange of ideas on topics like this.