Well, the physical world is the last place where I still have to see ads. So I guess if you want to appeal to an adblock-using demographic, it might make sense.
It's actually kind of funny that here in London, we want to encourage people to take the train, but we simultaneously scream at them that they're too fat, poor, and bald.
Actually, perhaps "funny" isn't the right word...
Of course, immediately after that, someone brought up the fact that they can't afford 8 pence. I figure they must have spent it all on hair loss products from the advertising.