They really want to make sure you know which door to use.
The funny thing is: I still reached for this one (even if momentarily) right after taking the photo!
(Every time I go back to this restaurant I remember that I still haven’t posted this photo, and by the time I have a chance to post it, I’ve forgotten again. Well, I finally remembered!)
Edit: I should mention that the door has been broken for several months. (I took the photo at the beginning of August.) I’m surprised they haven’t fixed it.
Update (Oct. 17): The door still isn’t fixed, but someone’s added another hand-written note to it since I was last there!