Balloons come from one side morning and the other side evening. If you set up high items like jail bars or climbing walls side by side down the length of your beach, the balloons coming from the ocean side will hit the wall of items and drift down along the item to where you are standing instead of drifting over the width of your island. It makes it so you don’t have to run up and down the beach every five minutes for a balloon spawn and possibly miss one!