I would only critique the shirt for being tucked in. I would much prefer to see a white t-shirt underneath it and the Hawaiian shirt unbuttoned.

There is also the British common law that anything twice done becomes a tradition.

My own philosophy is pretty close to Lawson's, "Great Scotch, no rules". Take a deep breath and realize that every kilt "rule", let alone every fashion "rule", is fraud. Not one can be substantiated. So, as you dress, think of who you might offend. If you don't want to offend them, dress accordingly. If it doesn't matter, dress as you like.

So, on our anniversary this past summer, I wore my kilt with sandals and a t-shirt to walk on the beach and lunch at a cliff side pub. Later, I changed into socks and shoes, and dress shirt for a more formal fancy supper. Still later, I was about to change to another black tshirt and boots to hang out with my daughter downtown. I decided to call it a night and didn't go. The point is that I kept the same kilt and sporran on all day and changed other items to what seemed appropriate at the time. I probably broke tons of fashion rules. Do I care? No, my fashion conscience is clean.

I appeal to an earlier tradition.

(Before anybody takes exception to my statement about substantiating, understand that even if you could find a legitimate originator of a fashion tradition, my statement means what does it matter, really?)

Fortunately, my clan/heritage has a strong tradition: Despite Them!