Because My Nephew’s Girlfriend is a Spaz
While certainly not recommended, a healthy adult cat can live in a closet for 62 hours without food or water. I happen to know this because a pet sitter locked my cat in a closet an entire weekend once.
Long story, but the moral is: make sure whoever is watching your pets counts them every day (also, dry cleaning removes neither cat pee stains nor odor so don’t even bother).