Extremely rare I use public wifi - there's a couple of places where phone signal doesn't work and I want/need some internet (underground, planes, actually on board the trains, some cafes etc), but at major stations? It's not like they offer wifi at stations where there's no phone signal (and if they did it would be better all round for the phone companies to offer 4g service instead)
What is the value proposition for wifi at stations?
What is the value proposition for wifi at stations?