Have a select-able option to auto kicks inactive players. This option would have options of how long a player needs to be inactive before being kicked. Examples 10 days, 20 days, 30 days, 2 months, 3 months, 6 months, 1 year. Warnings would be sent to the guild and the player within a window of time to warning of inactive kicking. This option would allow for easy reinstatement of auto-kicked players by having a kept record of auto-kicked players and being able to send a rejoin request easily made by guild members by going through this record and clicking on the name of the auto-kicked player and sending a rejoin request.
This option would be less intrusive on privacy than a “last been online” log of guild members.