I have addressed this issue by putting a small label maker label in the bathroom asking people not to leave water on the floor. ( some may think it's tacky, but when it happens so often and the molding is swelling....)
it is incredibly disrespectful to leave water sitting on a floor, except for maybe if it is tile. Common sense should dictate this. These guests have actually inflicted involuntary damage.
I also leave the shower liner inside the showers and the pretty curtains outside. I instruct my cleaners to leave it this way as a "HINT" to usage. I do several things like this around the house as a "hint hint"
you could also put specific instructions like this in your online house manual that they get when they make a reservation.
Good luck, as this is maddening.
Bella