As veteran of 67 years riding, BSc Safety Degree, over 1.5 million miles in 15-20 countries----all this worrying of getting hit from behind, maybe BS----paying attention to riding and what is ahead probably more important! My experience I have been hit from behind, once in WI----Lady on phone ran stop signs, hit me totaled scooter, hurt my hand. Got bumped in Toll booth in Japan, Sportster, strong rear fender=no damage.
Not keeping up with traffic---being too slow problem, sometimes hard with underpowered bike/scooter, dark clothes big problem but in my experience no amount of flashing tail lite is going to wake some people up