Annie Mole's, webmaster of Going Underground, daily web log (blog).
If you like this you'll LURVE One Stop Short of Barking, THE fun and informative BOOK about travelling on the London Underground.
He asked if there were any more like this. I thought there were. Certainly reminded me of some stickers I saw in "Look Mum No Hands" and a quick(ish) Google search revealed they do indeed have them.
As well as "Danger! Rudeness attracts Tube Mice", there's also Cheer Up Tube stickers for "Frowning on a Friday - Strictly Forbidden", "Fixed Penalty, All Sweeties must be shared & Chocolate" and "Loud music prohibited - Unless you sing along too".
"The magic, mystery & sometimes maddening shortcomings of London's Tube are documented with love, enthusiasm & sometimes despair by its unofficial social historian." The Guardian