Do you mean auto kicked from the alliance or the rank. Auto kicked from the alliance seems harsh but auto demoted is fine.
“BoH” (smartphone F2P, MMO, still running after 5 years) does the following:
After 30 days inactive for the leader (Guild master), all co-leader (officers) get the option “Take over this guild?”. Using this option promotes that player to leader (Guild master) with all the powers of the leader. The old leader (Guild master) is auto demoted to co-leader, retaining most of their powers.
Programmers Note: uses the same programming code as promoting a co-leader, but instead of being triggered by the leader player, is triggered by any of the co-leaders. If the leader logs in before the alliance is taken over, the inactive clock resets to 0 days. So a leader that logs in every 30 days always keeps the alliance.
After 35 days inactive for the leader (Guild master), all co-leaders (officers) and all elders (veterans) get the option “Take over this guild?”
The last rank member (recruit in Book of Heroes), never gets the option to take over.
In Book of heroes, the last rank, recruits (members in empires) do not get the option to take over. This prevents a player entering an abandoned, five year old, maximum level 40 guild with bonuses to all hero stats, and taking it over. To take over any abandoned guild (alliance) requires the player was promoted at least once to veteran (elder) by a co-leader (officer), or higher, before the guild was abandoned.
A guild master (leader) can also “lock” his guild (alliance) by demoting all players to the last rank, recruit (members in empires), but leaving the guild open to recruits (members). Thus declaring his intention to keep the guild, but allowing players to join the guild (alliance) and get all those sweet, sweet hero stat bonuses (Titan progression in empires). These are jokingly referred to as zombie, farming and parking guilds. Not sure how devs from Book of Heroes feel about this not dead but not alive guilds (alliances).
This seems to strike a balance between unfairly taking away a guild (alliance) you have run for 5 years and leaving a guild abandoned because the Guild master and officers no longer log in. But it does leaves a guild (alliance) abandoned if no promoted guild members log in. And it allows “locked” guilds (alliances).
***member (no promotion required)