This ought to be the canonical definition of an ambiguous sentence: a sentence that can reasonably be interpreted in materially different ways. (Ie: not something that makes sense one way and nonsense the other.)
Ideally it should be:
a) an instruction, order, or injunction (as above);
b) interpretable in mutually contradictory ways;
c) demanding correct interpretation to prevent catastrophic loss of life and/or property.
The don’t want everyone to understand the reality that they chopped about 30% of the movie off at either end of the image so it would “properly” fit their TV screen.
People have already mentioned about the Slow Children. But it’s really our fault because we send them to a Slow School.
One of my favorite ambiguous sentences was from “Police Squad”.
Ed: “We found the ransom note. We sent it to the lab. They want a million dollars.”
Frank Drebin: Why does the lab want a million dollars?
Once I heard a news report stating that someone was “shot outside of a church.” Seems as if that Church was getting circus performers to climb into cannons and get blasted through a stained glass window.
I went home to get my camera and then I returned to take a picture of it. By the time I went by the restaurant again the next day the sign had been changed to read BROILED HALF CHICKEN.
That’s for when they can’t fill the drive-thru customer’s order quickly enough and rather than back up the whole line on one big/custom/odd order, they ask you to pull up and wait in a particular spot just ahead of the window. That way people behind you with orders of one burger and one coke can get sent on their way, while another worker fixes up the specialty sandwiches and stuff for yours.