If you want to be safest don't drive one of these things. On the other hand if you have the racing seats you can install 5 point racing belts and you will not hit your head or fall out of the car, even if the seat breaks free. Upside down however you are f...ed.
You are absolutely correct. I wear a helmet when on the track AND my removable and frame-mounted 3 point rollbar is installed.
Otherwise, you'd just be an eraser!
On the street, just use your Spider senses, keep your eyes and head moving, and like others have said, leave an out.
I was rear-ended in my Spyder at a light, but the guy who hit me stopped as well. He forgot I was there and jumped as soon as the light changed. But my car was silver, which is basically invisible, as it is close to the gray of the pavement.
My one pet-peeve, lookie-loos on the interstate who sit in your blind spot. I usually just squeeze the throttle to about 110, and leave it there for a bit, and then slow back to cruise. Usually that gets rid of them.