I like this idea quite a bit. And I feel it is necessary to reinforce the SMA.
What about creating a record in the family history that read is follows
- On DATE, Swore fealty to CHARACTER/TITLE
- On DATE, Released from fealty (Add a button option in politics to ask to be released from Oath, Lord then gets a message and approves/declines)
- On DATE, fealty revoked for REASON (If displeased with a vassal, a lord may dismiss them with a msg explaining why, much like judges to banisments)
- On DATE, Broke fealty for REASON (Leaving estate without permission; prompted to add reason why as above)