[yardstick]

One thing I’m conscious of with these crowded escalators is the exit point safety, as some people can be rather slow to move away. Making both sides standing would make me concerned about seeing accidental pileups from people not moving away quickly enough.

You get it sometimes already when the station itself is overcrowded- TfL normally starts limiting access, running congestion control etc. Fortunately most of busier places (Bank, Canary Wharf, etc) are full of regular workers who know the drill.

It’s more one off special events where causal travellers show up en masse.