As a corollary to this discussion it is interesting to note that warg packs are paradoxically the most discriminatory and the most egalitarian groups that regularly form in the Ettenmoors. On the one hand you must be a warg to join (with very rare exceptions). On the other hand my experience has shown that warg packs will include just about any warg that wants to join regardless of how low ranked they are or how little Audacity they have. The fact that the person wishing to join is a fellow warg seems to override any other consideration.
That is not to say that that is always the case. For example, sometimes on my server (Laurelin) there will be packs formed that specifically ask for rank 10+ or rank 12+ wargs. These are usually small packs and more aimed at allowing more high ranked wargs to play in a pack without leading to give them a break or perhaps in response to a specific threat e.g. a particularly potent small group of freeps.
The general rules stands though: if you are a warg and there is an open pack you will not be refused admission.