1) Have you ever been assaulted while riding? What happened and what did you do?
I have been assaulted or threatened with it several times over the years while on a bike. In particular I had a boiled egg thrown at me once and was driven off into a freshly cut ditch. Could easily have died, got lucky. This was back before cameras, and had no real information to follow up on.
I was run off the road during a commute home one time. It was honestly mostly my fault for shooting a bird at the driver through his pickup truck window in front of his girls face.
The latest occurrence was some years ago. I got buzzed by a guy and held my hands in the air in the easily recognizable "WTF" pose. He came back around, buzzed me again and pulled to the side of the road. I passed him as he was getting out of his car and he rushed towards me. As I dismounted he literally ran into my prosthetic foot and knocked himself out. By pure luck there was a police officer leaving his home right in sight of the whole thing. It was thrown out before ever reaching court as the guy had a history of "craziness".
2) What measures have you taken to defend yourself and how far are you willing to go?
Of these instances only one of them even presented an opportunity for me to have taken measures. I am a pretty big guy in stature. I have been lucky enough that since my adult life (at least) that presence has been enough to dissuade most people from escalating beyond a bit of raised voice. I have taken enough martial arts to be a danger to myself (lol), and I don't carry a gun or anything. I would like to hope I never find myself in a position to NEED to take things to a next level.
3) This one is personally important to me. If you primarily ride on one particular Bike Path at specific times, sunrise and sunset, and were assaulted one evening on that Bike Path, would you just avoid that section of the Bike Path in the evening, which is the only time they would be there, or would you ride anytime and anywhere you wanted even though it might mean defending yourself using very drastic measures?
Honestly, I would be very careful where you tread with the thought process that could be interpreted from this line of question. It could easily be interpreted as preconceived desire to do harm to someone. Do yourself the favor and just avoid the area for a while. If you were to even see the individual(s) in question at some later point, turn around. Perhaps get yourself a video camera, etc. such that you might use any interaction footage as both protection and/or to perhaps use for a PRO or other measure.