Well! I went in to write on the mirror tonight, and everything was gone. Still without a word. Which leads to the thought that when she asked the kids not to clean the mirror it wasn't because she wanted to save the stuff, but that she wanted to do the cleaning, rather than "making" them do it.
But, I still managed to write: Do you want a banana split when you get home?
With check boxes for yes and no.
I was disappointed to see everything gone, without even a word.