It's odd and sort of interesting that one of the best Pipe Bands in the world, and located in Scotland, wears large clan crest cap badges on their kilts in place of kilt pins.

It looks strange to me.

As I explained to a fellow piper, "you know, they make special badges just the right size and shape to wear on the kilt...
they're called kilt pins!"

But historically this band might be in the right: in The Highlanders Of Scotland only six of the 33 kilted figures having that part of the kilt visible have kilt pins: two open circles, one open oval, one looking like a modern clan crest cap badge, one the crest without surrounding circle, one a complex design. No blanket pins, no pins shaped like "classic" early 20th century kilt pins (sword & targe etc).