Setting limits on noise around residential areas has merit. Everyone's opinion will vary but IMHO some things are just too loud and not in a pleasing way either. For example, a roadglide with short, straight pipes passed me on a busy freeway and I could still hear it 1/2 a mile away. I also heard a set of UFO pipes on a VMax that I would consider too loud but the owner loved them and thought they were sweet.
However, why single out motorcycles? I've been awoken from a nice sleep by 4-banger tuner cars, muscle cars/trucks, as well as some car audio systems thumping so why not target those vehicles/drivers? If a decibal-recording device can be used to measure motorcycle noise, why not car exhaust noise or stereo noise?
You'd probably be safe on any country road, highway or freeway but be careful in small towns, especially in the residential areas.
Blaine