On the lid of the coffee cup: Contents may be
hot.
On a package of
kitchen knives: Caution! Items are sharp.
On a trash
bag: Do not place over head.
At a railroad crossing: No parking.
On a clothes dryer: Do not place children or animals inside.
"This is the dumbest sign I've ever seen. Do they think I'm a complete moron?"
"Dude. Gotta plan for the Dumbest Common Denominator."