The reeds of course are potential places where mold can grow, but in a bagpipe and some other instruments the reeds themselves aren't "in your mouth" as they are with clarinets, oboes, and saxophones and the like. It seems unlikely to me that the reeds in any of the common instruments would be the main place where crud and corruption could flourish. It's likely the larger surfaces of the instrument that get moistened by the breath that passes through that would be where fungus would flourish, but any surface where moisture is present could contribute to the problem.

Conceptually, one might think that harmonicas would be the biggest threat, since you blow, which makes the innards wet, and also suck which draws the mold back in. Fortunately(?) the much smaller area on which the crud can grow seems to make the threat tolerable, and harmonicas may be easier to "sanitize" than some instruments with larger area(s) on which the mold can grow - or at least they might dry out sufficiently to inibit/slow the growth of the nasties between sessions.

I doubt that worrying just about the reeds will be any great help. It's the cleanliness of all the innards of the instrument exposed to the breath that needs to be of concern.

Maybe our bagpipers need a discussion on "how to clean your old bag" as much as they need to worry about just the reeds. (?) And maybe it's also just the pipers** who suck who are in real danger (?).

** probably applies to other instruments.

John