Reflectors do work
A while back someone posted a link to an article suggesting that reflectors on bikes are basically useless, as a car has to be directly behind the reflector in order to see the light reflected from it. I believe it was in a thread talking about removing wheel reflectors.
Last night I was driving home after dark and as I came to the outskirts of a town up ahead I noticed the familiar loop-de-loop of a pair of wheel reflectors. The cyclist was crossing the highway and going down the street I was going to turn on. I think he was roughly 100 yards ahead of me when I noticed the wheel reflectors. Knowing that he was going the same direction I was headed, I was a bit more cautious after I turned, keeping my eye out for him. I saw his red rear reflector and the up/down motion of the pedal reflectors. He had no lights on his bike whatsoever.
The point is, had he not had the wheel reflectors I wouldn't have known there was a cyclist up ahead and going down the same street I was going to turn on. Had he not had the rear and pedal reflectors, chances are I wouldn't have seen him until I was very, very close, and with the headlights of oncoming cars, it could have been a very dangerous situation.
True, it probably would have been better had he had lights on his bike, but there's no mistaking the familiar pattern the wheel reflectors make.