I have two Dirk's and neither one would be well placed at a ren faire. This is because they are both Victorian style. They could be worn with traditional highland dress but as has been said before me, in modern times these seem to be going they way of the do do birds in terms of formal wear. I think this is because they are the last of the vestigial weapons and as our society gets more and more weapon free (for better or worse) these are seen as either quaint historical oddities or something to be discarded.

As an aside to your remark about being allowed to have such things, I live in a state where a dirk (called in the statute a dirk knife) is one of a short list of weapons that require permits. I have never been questioned when in highland dress, because even though uncommon, they are still considered normal. When I was part of an organized color guard I looked into the permitting process and gave up in confusion. Since I rarely wear my dirk nowadays it is really not an issue.

I would love it if there were more chances to wear dirks, as I think it is a nice tradition, however it is also not really that functional any more and gets into the area of peacocking when worn at most events. They are doing me no good in the closet.