Just saw this for the first time

Every cell phone in Tokyo has a camera. More than half the women under the age of 30 in Tokyo wear very short skirts year round. This is why all the cameras on all the cell phones in Tokyo make a noise whenever you take a picture. You can disable/modify any sound on your phone except the camera. This is why.

This sign is up on the escalator in the Kichijoji train station. It's fairly common to see women holding their skirts close whenever they're on an escalator. Trains also have problems with groping when they are very crowded. By very crowded I mean that the last four or five people are jammed into the car by the force of the doors closing on them. This is typical traffic heading into Tokyo in the mornings and out of Tokyo when people get off work. As a result there are cars designated just for women during certain peak hours.

I don't know enough about Japanese men, or the dating scene or homelife to offer any insight into this. I think I'm cool with that though.