Brickmuppet reports:

One surprise (to me anyway) was that the men and women are in essentially the same high ceilinged room (vaulted ceiling topping out at 40+ feet) seperated by a wall only about 81/2 feet high. The women could be heard on the other side, chattering and presumably doing the Natto dance. This arraingement greatly facilitates the airflow of the place, but given that I'm just over 6 feet tall, had I been obnoxious and stupid, mischief could have been perpetrated. The various Japanese shows where this apparant design flaw is a plot point do not, it would seem strain credulity.

I'm 200cm tall and yes, I did delight Japanese by hitting my head forecefuly upon various train appendages on Yamanote. Still, a 8.5ft wall would be tough to look over without using a stool.