Here is something that I found on Matt's blog, I think it speaks directly to this thread. It is also something I must remind myself of from time to time.

Advice for every kilt wearer
"The Highland dress is essentially a 'free' dress -- that is to say, a man's taste and circumstances must alone be permitted to decide when and where and how he should wear it... I presume to dictate to no man what he shall eat or drink or wherewithal he shall be clothed." -- The Hon. Stuart Ruaidri Erskine, The Kilt & How to Wear It, 1901.