AITA for putting a “Do Not Disturb (MIL)” sign on our nursery door?

My MIL has been popping in to our house multiple times a week since we brought our newborn home (usually unannounced.) And she always opens the nursery door, even when the baby is sleeping, just to “check on her angel.”

I’ve asked her to stop. She said, “I raised babies, I know what I’m doing.”

So I made a literal sign that says: “Do Not Disturb, that includes MIL.” She saw it during her last visit and stormed out. My husband said it was “provocative.” AITA?