I have mixed feelings about this. The musician and occasional busker in me objects on principle. On the other hand I wouldn't want to have someone playing music (however pleasant and tasteful) for hours on end outside my house or workplace.

Buskers can make a positive contribution to the ambience of an area, but they can also be a bloody nuisance. Amplification is certainly a problem, but acoustic bands can also be loud. I frequently see a brass jazz trio plus accordion and snare drum and they're pretty loud. As for bagpipes...