I'm sure I'm not the only one who doesn't the ads back after the maintenance is done.
I never thought I would have said that a tube station felt like the calmest place in the city, but mentally, it has an enormous calming effect to not be surrounded by messages.
I wonder if the "Journal of the Mental Environment" has documented the place???
I guess, being cynical, the first brand to pay for keeping the place brand free would get loads of great advertising/brand value (ahem, cough…) from doing so…