I had this happen as well. I had a guest who had two reservations with two day break between them so she could drive down to Florida and see family then on the way back stay again. So at the end of her first stay she asked if she could leave a few things in the fridge, if no one had booked those days between, and offered that I need not clean the rooms. I agreed as it was within 24 hours I assumed no one else could book. Well I wake up next morning and someone booked those nights. Very stressful but the guest was so nice and understanding and left great review. It was still very awkward, as I had to move her things out of the fridge. I also thought one day meant 24 hours and a very careful reader. All of these little things can add up and make you more stressful especially this year.