To save lives of motorcyclists and padestrians.
As a motorcycle rider of 39yrs experience and a car driver of 30yrs i feel the laws and mot rules on motorcycle exhaust noise levels are an out dated and dangerous.
If a motorcycle is quiet,a pedestrian or other motorist(car and loud hi fi),are 100% unaware of where the motorcycle is or of it's excistence.Loud motorcycles attract attention and thus heighten others awareness off their prescence resulting in less accidents-"i did'nt see the bike/hear the bike".Also if a person was acting illegally on a loud motorcycle,police are able to track the motorcycle by the noise.
I have always had loud exhausts and i have only ever had one accident of a van turning and colliding with me-i had a brand new bike with quiet exhausts and am certain that if the loud exhausts had been fitted i would not have been hit.
So as you are looking at reducing the amount of unnesassary laws,please consider this as a safety issue.