Yes I think the Scots would love it.
Highland Dress isn't required by the RSPBA, and some Scottish juvenile bands compete in trousers, while Breton, Galician, and Middle Eastern bands compete in their traditional costumes. As long as its "matching dress" it's fine by the rules.
Discovering this aspect of the RSPBA rules several years ago led me to think of American applications such as:
Texas band in matching cowboy boots, jeans, Western shirts, and cowboy hats
West Virginia band in fringed deerskin shirt and pants, with raccoon hats
Hawai'ian band in matching aloha shirts
The traditional Appalachian costume:
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