Yes, the FAQ is very helpful, but what I've found is some cracks in the scheme of things that seem to help keep a reputation intact.
Firstly, BB status does have a decay rate, though I don't know what that is per' se. Still, if one waits long enough it will come down eventually.
Secondly, strategy plays a large part in controling BB status.
Let's say there is this break-away count. What the soverign need do is bring him back into the fold, but avoid the BB hit.
If one already has a claim to the count demise, that's cool, otherwise one must grab the title and suffer a slight hit to BB.
Now, with title in hand, attack the count and storm the castle. In the negoitions to follow, simply force the count to become your vassle and return the demise back to him. This strategy avoids the larger BB hit that would accrue if U kicked the count out.