@Bianca156
I would politely send them a message via the ABB message platform.
"Hello ------
We hope your stay has been great so far. I have cleaned the room and stocked the bathroom of towels and toilet paper.
I also noticed that the you have placed bag over the tray table from the kitchen. Those trays cannot carry that much weight and will eventually break. I would strongly advice that you find an alternative place to place your bags. I would hate to charge your deposit for damages whilst it breaks.
Message me if you have a question. I can help.
Best,
Bianca"
Always begin and end a letter with a positive phrase. Sandwich the unpleasant stuff in between.
Communication is key. Your guest will not know your expectation of you don't communicate.
Good luck.