Isn't this a little intrusive? Ah, the news media, acting like little chidren - except some little children have manners.
If (and BIG IF as it does not seem to match his handwriting) it is him, I think some serious questions need to be answered. Security questions.
I cannot imagine Secret Service allowing this to go by unnoticed. I bet the photographer gets a knock on the door.
What if the note said anything related to sensitive information normally not shared with the world?