FWIW, I guess most of us usually think of having a collision with another vehicle as a bike contacting a cage, not another bike. My closest vehicle to vehicle call was with another motorcycle, being ridden by my wife, coming up from behind. Several years ago we were out on a cruise, she bringing up the rear, as is normal with us. I made a sudden decision without signaling to turn around and visit a tourist site. I hit the brakes to do a U-turn, she was not paying the closest of attention and missed rear ending me by inches. For my part, I realized that if she had been in a car, I would have been toast. It scared the crap out of both of us.