Re: how loud is an HT from the cager's perspective?
Like Jax2a said...it's a matter of two wrongs not making a right, really. your best bet would be to A) look into your state's if not city's specific laws on registration and what needs to be made to make your bike legal, as ignorance of the law is not an excuse for breaking it, as the judge or officer will tell you directly. Second, always carry a cell phone with video and pic capabilities. If you would have gotten his license number on film and videotaped your confrontation WITHOUT flipping him off, then you would have had the law on your side.
As for turn signals, yes, they can be required. Here in Michigan the letter of the law is that ALL motorized vehicles must be registered with the state, and that they need blinkers, a front and back light, a brake light, and a horn to be considered street legal. A few towns here have officers who are lax on the law and let you get away with turn signals, but sure as sh!t they will throw your bike in their trunk and impound it if you get caught speeding on an unregistered and unlit vehicle. Again: Check your local laws. It took me all of 5 minutes on my computer to do so.
when you are on one of these things you are representing ALL of us, and influencing the cager's viewpoints on us as well as dictating the course laws will take. And ultimately in the fight between a one ton car and a 80lb bike, that car? It's always gonna win.