Does this have a specific legal meaning? See it everywhere.

Surely you just word the notice correctly and will be implicitly polite.

This probably could have been tacked onto Noah's thread but I wanted the attention.

ALSO

I saw it on a hi-viz tabard worn by a horse rider the other day with the "POLITE" big and the "notice" really little so it looked like a police hi-viz tabard to cars overtaking. CLEVER.