@Sammy, the occasions when the server is completed filled with XI members only is infrequent, so I haven't noticed whether it will re-direct a spec or not, but I have seen it re-direct an XI member before.
@Angelz, it is an automated process for a reason. It is randomized, and seems to be the fairest way to choose who is going to have to leave in order to make room for a clan member. With such a busy server round the clock daily, admins would not be able to keep up with constantly checking to see who they could ask to leave the server with all else that goes on during their watch. The re-routing is a clan choice, as it keeps players within our servers, and oftentimes when it's really busy, several players get re-directed at once and they end up playing on whatever mod it is. I always watch for that myself, and often have gone into the re-direct server when there are several players and play there myself to get more traffic. I'm not sure why you keep deleting the map and mod, but I think it would be pretty safe to say that most others do not do that every time.