Who cares if it is legalĀ

BigDog Motorcycles outta Kansas used those in all their bikes untill 2004 when one state made it illegal.
Research showed that the modulator made a motorcycle 40% more visable to a person behind the wheel of a car/truck/etc.
I would say go for it. It is your but on that bike , you need all the help you can get in a sea of Suburbans and Excursions....
I had it on my last three bikes , and allready have one sitting in my tool box for the cb project.