The other big problem with a clan is not exactly how well they coordinate, but rather how consistently they move together.
If you've got 20-30 people who can all be counted on to move no more than an hour before the turn, every turn, that will more or less guarantee you can win a war against any single realm in BattleMaster. Heck, even just that many people who can be counted on to move to the right region every turn could probably do that for you.
Most realms can't manage that these days by pulling from the general BattleMaster population.
So basically if a group of friends play together but follow the IR and remains inclusive, then that is all right.
However, if a group of friends asks their friends to log in at a certain time by OOG means, then it's not legit.
It seems to me the IR are truly well written from that point of view....
