hm i would simplify the rules to turning someone who makes stale turns to ai :
1. if no reasons are given after 3 stale turns in a row : ----> set to ai
2. if you go to holiday : then you should try finding a sub for these 1-2 weeks .
should be not too hard
if you really find no sub which is very unlikely then what has to be done should be chosen from case to case .
3. if something bad happens ( hopefully not but it can like accident ) try to inform someone and then here a pause for 1-2 days until the player has time again should be the general rule .
if something really evil happens ( hopefully not but a small chance exists , norfleet would call this a gruesome accident
) which Lasts longer then a few days a sub should tried to be found or turn the player to ai after you gave him best wishes for fast recovery from the evil thing that has happened .
in 99% of the cases only point 1 or 2 should happen point 3 was only to be complete ( hopefully this happens nobody in any game )