its the same sort of thing with letting humans into your cade after the zombie has spawned.
you cant do it because its way to easy for them to get zombiefied when you open the cade for them, and if they break it trying to get in thats even more of a pain in the ass.
thats why when the cades shut unless the owner lets you in you go somewhere else and if you break in its a ban.
Edit: Valve AND Zero would find a way to screw up a steel ball.
I have never seen any other server that used to be so much fun to play on just get so properly rammed into the ground by one person's lazyness, incompetence and inability to grasp how to properly run a server.