It is always good to see workers of large corporations taking the initiative themselves. It looks like at Shibuya station, they decided there was a need for a sign in the elevator and they had to make one themselves.
Although it looks hand made it is great to see the art work that has gone into this poster and the way it has been properly font colored, emphasized and then laminated. It is nice to see that even though this looks like a one off poster it was done right.
The poster says, “Be careful. If you jumped around you will get stuck in the elevator, please take care.”
You can find the poster in the elevator at Shibuya station on the Yamanote line, for trains headed towards Shinjuku. The elevator is at the rear of the train towards Route 246.