Owner Key:
Owns capship and is the only one who can activate insurance and dismantle the ship.
Can issue and revoke keys. Ship cannot be sold or dismantled if more than 1 player holds an Owner key. Cannot issue or transfer Owner key until game changes and allows inter-player ship sales.

Guild key: Grants access to a guild. The owners specifies Captain/Pilot or User Key.

Captain/Pilot Key:
Can operate ship, dock with ship and operate a turret.
Can issue and revoke user keys, can gunner kick.

User key:
Can dock to, ride in ship or man a turret.
Can be issued to a guild and all guild members gain key. Revoking guild access automatically revokes the key. Leaving the guild drops all associated guild keys.
If gunner kicked either automatically undocks from ship or if trident is docked at a station is returned to station. If kicked in space and does not have a docked ship is returned to home station.

Any player can be gunner invited when capship is docked. Player is returned to home station when gunner kicked and doesn't have a ship docked or is not in station.

Good ideas as part of an overall restructuring of the keychain system.

How about re-instate the ability to create multiple user keys in a sane and manageable way so that the permission checkboxes are actually useful for something?

+1 to the ability to add guilds to the access list.
+1 to more granular controls over turrets, docking, repairs, piloting, etc.