For a war guild to have permanent members, no kick and recruit, and to be sucessful would be near impossible. 25 people. C'mon guys. That's why the Ally system has been used for sub guilds in most war guilds. For SoS, ~100 members that work together and know each other.
I for one never change guilds whatsoever. My GST teams have all been made up of close friends to the guild members and the members themselves. While some members may never switch, I don't think there is any single guild where all the members are strictly on tag 24/7.
@OP, Charm's allies are basically friend guilds, I don't think they've used the ally system in the way you seem correct either based on that logic.
@Rufus, you win internets.