Elaborate.
I kinda like to keep my things short in simple, but anyways this could be abused on fear tower. Fasties could jump under other zombies who are trying to make their way to the to, thus making them fall and having to restart climbing once again. Not only that, but could other fast zombies knock other fasties in the air? If so minges could easily interrupt a players pounce, and as stated before, ruining the players gaming experiences.