Good point Minorl. Now also think about the effect not on the audience, but the musicians. Surely one would think that a musician can play more passionately when he/she doesn't hear distractions from the audience, so the quality of the music being played would be more emotional and enjoyable.
So, think about this: Maybe someone sitting on the opposite end of the theater wouldn't hear a cough or sneeze, but the musician did. So the music suffers, which in turn affects him anyway.
So, think about this: Maybe someone sitting on the opposite end of the theater wouldn't hear a cough or sneeze, but the musician did. So the music suffers, which in turn affects him anyway.