I disagree with your band members Graham, kilt pins intended for gent's kilts are available from all the top kiltmakers in Scotland, and elsewhere. I think a kilt pin adds the perfect finishing touch to a kilt outfit. Perhaps your friends were talking about the large safety-pin style pin, often seen on ladies kilted skirts.
I had exectly the same thought, Martin. The large 'safety pin' style seems to have gone right out of favour for us chaps and it is mainly only the ladies who wear them now, on their kilted skirts. When I began 'kilting' in the early 50's those were just about the only type of kilt pin available. I remember flipping when I saw my first sword kilt-pin years later. It was in solid sterling silver and I believe I saved my pennies for many months to be able to buy one like it. I wear it still, with my dancing medal, on my 1973 Ancient Gunn kilt.