From MY PERSONAL experience, almost everytime there is one or two survivors left they just go into the sky and sit up there with umbrellas until the round is over. Making them a huge pain not fun to deal with. And it doesnโt help that goblins have way less stuffing compared to the survivors. (also 90 percent of the time they are moving too fast and or they are too far away to hit with projectiles) Iโll elaborate when I can think of what to say. A lot of other people in goblin war also donโt like to have to deal with sky campers so banning umbrellas would boost the experience.
tldr: ban umbrellas to prevent sky camping