Despite the unusual nature of a kilt...similar to all the other culture-specific daily wear clothing I don't know the names of...it's an article of heritage and culture, not a statement or anachronistic costume.

...Or "cosplay", which I had to look up, and which seemed better defined on UrbanDictionary than Wikipedia.

People make it either or neither of those things based on what they wear with it.

Jacobite shirts, fairy wings, vampire teeth, and too many clan badge accessories make it a costume. Disagree? When was the last time you wore any of that stuff to the mall, with jeans? Not that I have a problem with Jacobite shirts, per se...only that I think they're costume, not "just clothing".

A t-shirt makes it clothing.

A ball gag hanging from the belt would make it a statement .

vampires (sparkling or otherwise)
Sooo...I'm envisioning a hot gothy mess with plastic fangs and glitter makeup. Am I close?

...And where is my snark icon?