All over America, restrooms for the public (for example, in restaurants or public parks) have signs warning and exhorting us that "Employees must wash hands before returning to work" or "Hand-washing stops the flu!" These are useful public-health messages. However, in almost every restroom I've been to, the sign stares at you from the mirror behind the sinks. What is the point of reminding the already hygiene-conscious to wash their hands?
But in the San Francisco airport a few days ago, I finally found a "Clean hands, good health!" sign at the restroom exit door. I don't know whether it ever caused someone to U-turn and head for the sinks, but at least it isn't carrying coals to Newcastle.