I remember hearing a few months ago that in Hungary they've passed a new law that permits only women with "good legs" to wear miniskirts.
Actually, it's one of the few ones here that makes any kind of sense, but doesn't it mean it must be determined somehow that you have good legs?
And yes, that does sound like Discworld, though it also reminds me of a Monty Python skit. This guy knocks on the door of this house and politely tell the lady who answers that he is going to rob her house and asks to be let in. However, she 's reluctant to because she suspects him of being an encyclopedia salesman. Good one, that. *chuckle*