Not sure why someone would not want to use lights on their bike.

I live in Florida, possibly the world capital for "distracted" drivers. If I could find a shirt with bright strobes attatched I would buy it in a heartbeat.

Probably one of the most popular vehicles here which is most likely to hit a bike would be a pick up truck hauling a trailer with either lawn or construction equipment. Never fails. You read about at least 3 accidents here per week involving a pick up truck with a trailer hitting a bike rider.

Would a bike light help that pick up driver drive any better? Probably not. However, at least he would be able to see you at a distance (especially if you have a bright, blinking red light).

Why do some people choose not to use lights on their bikes? Who knows. They are probably the same people who ride with dark clothing, no helmets, against traffic, etc.