Okay, if this is on paved multi-user trails or someone using overly bright lights on a group ride I could understand. On the other hand if this is about observing a cyclist as he rides down the road from a car or other motorized vehicle I would have a hard time understanding. BTW my eyes are astigmatic and tend to gather more light than needed. I guess this why I have good night vision but yes overly bright lights bother me too. Generally when I encounter bright lights I try to look away. When driving at night most of the overly bright lights I encounter are from cars and pick-up trucks. I just deal with it because it's not worth getting into a huff over. I only ever encountered a bike with overly bright lights once. The guy was in an urban area and riding on the side walk and was facing road traffic. He was using two cheap Chinese Magicshine type lamps on the bars so maybe 1400 lumen tops. While I noticed him it was just because the bright light and the two lamps drew my attention ( and I am into night riding ). He was far enough off the road not to blind me so really I paid it little mind. I made a mental note of it though but only because it was the first time I ever saw someone with bright lights riding on ( or near ) a road. If he had been riding "with the traffic" I doubt I would have even noticed him since he was on a sidewalk.