If the devs think it will not be added, they rule it out, then tell twister to edit his post (the sticky). That, however, takes a while because twister is not the most active mod out there. Sometimes, it just isn't update it. But in any case, the devs may have ruled it out at one point, and later they thought it was a good idea. They decided to develop it. The ruled out list is basically "This probably won't be happening, so please don't post about it." It is not "There is no possible way this will ever be in the game, so don't even waste your time." They don't want the forums to be spammed, and they want an official list of things that will probably not happen.
