Our neighbors at the park we are at have a rope with 1gal milk jugs tied to it about every foot or so. They have extra length on the ends and will pull the milk jugs under their large awning topper and I can see it works. When they leave they can remove it from the ground by just pulling the rope.
Even though I thought it a little ingenious, I don't see myself doing it to my slides even though they all pool water.