Proof was asked for because data beats anecdote every time. Why do I need to see a cyclist at 600 yds when my braking distance is a fraction of that? Why aren't pedestrians encouraged to dress this way? Why aren't cars (oh so many of which around here have filthy number plates and defective lights) all bright yellow and covered in diamond tape?
So...
How many ninjas have you run down when driving? I'll wager the answer is near zero.
How many hi-viz types have you run down when driving? I'll wager the answer is near zero.
I think the answer is simple. You're looking. (Probably, I'll wager, because you are a cyclist) You aren't the problem.
Why do hi-viz types and ninjas alike suffer close passes in broad daylight?
Have you seen/read the attached document.
http://eprints.qut.edu.au/38338/1/c38338.pdf
In the controlled tests carried out that are described in the study:
When wearing black cyclists were recognised 2% of the time, reflective vest 50% of the time and vest and ankle reflectors 90% of the time.
You are not forced to wear reflective clothing when cycling but to state that they provide no benefit is wrong, without doubt (and as proved in the above study) they improve visibility. What a driver then does with that information is up to them.
In answer to the question why do I need to see a cyclist at 600 yds when my braking distance is a fraction of that? Well if you haven't noticed him for 500 yds you have still have an opportunity for his reflective jacket to improve your chances of seeing him for the next 100yds, unlike the ninjas who I often only spot 20yds in the distance.
I will accept that hi-viz has very little benefit in the day, it's all about contrast. I wouldn't recommend cycling in c
amouflage gear where I live as you will look like a hedge and probably get hit by some blind OAP, however, a strong colour would be recommended. Reflective provides that contrast to the dark at night in the best way possible with the exception of good lights, in some cases reflective is sometime better than the red things some people fit to their bikes.
PS how many cyclists have I knocked down? One ninja cycling behind the back of my car while reversing, not proud and felt like killing the idiot for doing what he did, but he was young and not taught any different. I also try to eductate the local kids when they cycle on the road with no lights at night by explaining that I cannot see them when driving.