Platform-edge-sitting would seem to be something which very many people, of very many categories -- common denominator, their not being very rail-savvy -- tend to do.
I recall an occasion about ten years ago, involving myself and my brother, who was then aged about fifty. He's a very intelligent guy; but he hates and despises public transport of any kind, and has as little to do with it as possible. This was an occasion of, for him very rare, rail travel: we had taken a river / canal-side walk from Newbury to Aldermaston, and were on Aldermaston station, awaiting the next local rail working back to Newbury. Weary from the walk, he sat down on the platform edge, legs dangling over close to the running line. I remarked to him, "that's not a wise thing to do: non-stop trains come along here very fast". He didn't immediately, particularly respond; but in time, of himself (to my relief) got up and stood on the platform. Not long after, a westbound express train rushed through the station, past the platform edge adjacent to us. Brother said to me, ruefully: "My word, you were right."
It's good that some people are able to learn, and acknowledge reality when they experience it.