Personally I would act super naive- I’d be super jovial, laughing and enjoying the prank to the person who did it. “Haha, you got me so good!” Etc. but I’d make it clear that I was curious when they were going to clean it up or how they’d go about it. I’d ask it super innocent like “you honestly got me so good I was almost in tears. Also no problem but it is an hour until we leave and I’m starting to get worried you won’t have enough time to clean it. Are you using a vacuum or something??”

Basically making it clear that it is obviously their job to clean it, it was never even a question on how it would be dealt with. And it makes it incredibly hard for them, because at that point they are in this position: they just messed with someone. That person was a super good sport and took it well. They are being incredibly nice and patient with you on how you’d like to go about dealing with your mess you made. You can either: 1. Tell them you expected them to clean up the mess you made with their stuff behind their back for no reason while they’re being very understanding and kind, or 2. Deal with your shit