Japanese society is rapidly aging and the birthrate has been declining. Yet this is still a country where people don't seem to mind being treated or spoken to like babies. Manners posters are not uncommon on public transit here in Japan nor are they unheard of in other countries. But look at this example of cartoon chickens having a lively conversation on the subway and annoying fellow passengers. "Shhh, you're talking a bit too loud," the poster says. A yellow-hatted manner-police creature is blowing a whistle ("pi-pi!") to warn and shame the naughty birds. Despite having been written without kanji (just as children's books are), the poster is obviously aimed at adults, judging by the size of the chickens in relation to the rabbits sitting next to them.
I personally have no problem with manner posters telling people not to talk loudly while using a cellphone, but this poster essentially is telling people not to talk at all. Train cars are generally really quiet in Japan, as if you are in a moving library. People are exhausted from work and want to be able to sleep as soon as they sit down it seems. So any volume level of chit-chat could be construed as "too loud."
While we're not talking about fines or ordinances here, I feel like I am paying a price every time I see this kind of thing in Japan. Posters like this just enforce an attitude of "be on your best behaviour in public" which always comes across as a bit Big Brother-like to me. No amount of colorful and "cute" artwork can disguise that fact.