"STD - so the idiocy of the op makes it more important for her to have a go at the pedestrian so the pedestrian can learn to avoid such drivers in future?"
Did I not answer that when I said I would not reverse along a dark road to speak to a pedestrian, winterkills? For the avoidance of doubt, I have never stopped and berated or otherwise lectured any of the many invisible pedestrians or cyclists I have had to avoid when driving at night time and I do NOT condone what the OP did. However, neither do I condone what the pedestrian was doing. It is interesting that you seem more interested in making me out to be unreasonable, from one small point I made, rather than addressing the main points of my post, which I will reiterate below:
I genuinely believe that people do not realise how invisible they are, if they are wearing dark clothing at night - even in an area with streetlights, you often only see the person when they move, and the movement catches your eye - up to that point, they are invisible.
Yes, it is the driver's responsibility to give pedestrians and cyclists plenty of space, and to slow down when they pass them - but that is a whole lot easier if you can see the pedestrian or cyclist from further away. If you come upon them suddenly, because they are dressed all in black/dark clothing, you have far less time to react, and may not be able to avoid them. When our dses were doing their paper rounds, we impressed upon them that they needed to make themselves as visible as possible - lights on the bikes, hi-viz stripes, and the paperboy bags themselves are made to be hi-viz - they had to take as much responsibility for their own safety as possible. They couldn't force drivers to drive carefully, but they could make sure every driver could see them from as far away as possible.
Why is it a bad thing to suggest that anyone out on the roads should be as visible as possible from as great a distance as possible? If I thought there was a possibility that I might have to walk any distance at night, I would keep a hi-viz belt or strap in my bag, so I could put it on. If the car broke down, and I had to walk, I would put on the cheapie hi-viz jacket that is part of our emergency kit in the car.