I am not at all happy about the idea of changing how autopausing works. Fundamentally, it is based on the character itself: if you're not playing them, they shouldn't sit around making other people think they're active.
However, one thing that might be worthwhile is an indication on the family page that your character is close to autopausing, for both nobles and adventurers. That should solve this problem, as well as helping with some other ones.
