It's funny, I have heard people in-game complained about blocking the teleport entrance in fourcorners to the office upstairs. Not many people realize a poison or predxp can easily jump in from underneath.
Not saying it should be banned but we have been playing 4corners a lot this week and I am up in that office probably every other round or so and I haven't seen one zombie even dent the thing. Even when multiple zombies get stuck. If the jumper zombies are capable of jumping up through that square then in no way should it be banned, if they can't... perhaps something to look into but so many people go there...