I've been commuting to London on SWT (and whatever it was called before that) for best part of 28 years and not once have I witnessed a scenario whereby someone needing a seat hasn't been offered one. There again, I suppose 28 years of people behaving honourably doesn't make as good a headline as one isolated instance of people behaving like arseholes.
But I do agree with a minimum speed limit of 7 mph for all pedestrians. The amount of people I have to clatter into because they drift in front of me on my walk from the station to the office is ridiculous.