Why add a mechanic for this though, there are plenty of IC methods through the Judge etc in which to seek redress from a knight that has disregarded their solemn oath. Or you could appeal to the new Lord or whatever. I'm a big fan of having player initiated consequences for these things.
I also agree, but the problem I'm talking about is not
really a power problem more of a (I don't know what I should call it) tradition problem. Both a knight and a lord should be encouraged to stick with each other based on their mutual oath.
While I don't really think penalties would make a positive contribution, I think there should be some flavour text on the estate page to remind players how important these things were to medieval blokes.
