Sal's comment about the lady cleaning the subway in Tokyo left me thinking.  I hadn't really thought about the lack of adverts on those escalators, for there's so much advertising elsewhere

On the street

and here, on free standing A frames in front of an estate agents office (rather perilous for anyone with sight difficulties)

On the front of small shops in a busy street, where the adverts were a little overwhelming!

and inside the trains themselves, where there are not only the usual banner style ads but also a video screen playing advertising loops above each door, alongside the train information screen.

In fact, for most of the time, people are confronted with a huge amount of visual stimuli whilst moving about the city.  Not only that, but most people sitting on the train will be watching the small screen of their mobile phone, for though it's forbidden to make calls from the train, almost everybody is using their phone in some way.

But Sal's right.  Those escalators were an ad-free zone.  How very refreshing!