I only put two on all of the kilts I make, and I've even had some people bring me their kilts so that I can remove the third strap for them. As has been pointed out, it's not functional, not historical, and can actually adversely affect the hang of the front apron if pulled too tightly. Thoe who tell me they prefer the third strap most often give as a reason, "It's what I'm used to." And it is rather common today on most commercially available 8 yard kilts. But I know several traditional kilt makers who still leave them off.

Where did they come from? Click here:
http://kiltmaker.blogspot.com/2005/0...lt-straps.html