Phil - the count is up to 11 pages and growing.

Mael Coluim - the performer pictured is wearing what looks to be a contemporary version of the kilt. For some on this board the garment is not a kilt. (BTW - I own a Utilikilt).
For those whose traditional opinions which I deeply respect, while I am wearing a kilt (Tartan, wool, knife pleats, etc.) I respect the heritage of Scotland, and wear what is considered the proper traditional accessories. ( In this I agree with Jock Scot, Chef, cajunscot, etc.)
When I am wearing a kilt like garment (The similarity to the kilt is pleats in back and aprons in front, such as the Amerikilt, Utilikilt, etc) I dress in a far more casual manner to include flat caps, baseball caps, scrunched hose, sneakers, steel toed boots, lack of kilt pin, and whatever else.
While I am out shoveling that white s#@t that we have been overly blessed with this winter, I will wear a ball cap, so as to have the visor protect my eyeglasses from quickly becoming useless.
What hat is proper to wear with the kilt? I will stick to the Balmoral, and Glenngarry. Indoors no hat is worn and the discussion moot.
When I wear the kilt, I am being seen by the public as an ambassador of the Scot heritage. I should honour it properly.
When in kilt like garments, most of the public around here think of the Utilikilt movement. This is a U.S. thing from Washington State, that has become a popular garment with ball caps, T-shirts, work boots, and low socks. Just about as opposite to the wearing of the kilt as Highland attire as you can get.

My observation, and my tuppence worth.

I hope I have not offended anyone with this post, as it is intended to present a set of perceptions, that I have personally observed.
Peace