The Old Exploding Umbrella Trick
Click comic to ENLARGE.
The Tokyo Metro has been running a 'manners campaign' for several years, and each month publishes a new poster in stations. Over the months, the campaign has pretty much covered every bit of proscribed activity (don't throw up on your fellow passengers, etc.) imaginable, and three months ago moved on to behavior that is apparently encouraged. The above images are 'repurposed' from campaign posters.
[To see other cartoons and comics in the Tokyo Metro series, click here or on "Tokyo Metro" in the labels below.]