You cannot walk out the door twice without coming back. You have to walk out, come back and walk out again. Therefore, by asking this guy to walk out twice you ask him to walk out, come back and walk out again. Therefore you ban him (walk out), un-ban him (come back) and ban again (walk out the second time). Since this thread is only about banning someone and not un-banning you are banned for not following the rules. Now, walk out the door