I always wear a pack. We usually march in white shirt & tie with a gray vest- I find that the straps and pack itself blend-in to the vest well enough, (my pack is black and gray,) that it's hardly noticeable. And having the backpack is nice to pack a spare chanter with reed, some water bottles in case someone else needs a drink, etc.
Our band is far from paramilitary, so that's different, of course. But I don't find it at all difficult to play.
In fact, I have a photo here from the 4th of July parade- the hydration backpack was the least impeding thing I was wearing that day...
Hey- maybe a set of matching packs, with the band logo, so everyone is wearing them would be a way to go, eh?
However it shakes out- stay hydrated!
