I guess I really an an old fuddy-duddy as far as this goes.

when piping in public, professionally, or such places as comps and the like, I would wear nearly at least semi-formal, if not formal, if it wren't out of place, say a PC at a highland games!

Definately long shirt, at least a waistcoat, semi, hunting, or hair sporran. Argyll hose, brogues of some sort.

I wonder though if the hair sporran and Plaide is not of the same nature as the white hose and short shirt, band inspired?