You say "used to"... What was the rationale for changing it? It's trivial for a judge to remove the ban, but impossible for them to impose it once the noble has left unless they get captured. Wouldn't we want to default to making the harder of the two automatic?
It was first changed when we moved to duchy-based region allegiance, with the rationale that a Lord's allegiance to his Duke is a feudal matter, and therefore something unquestionable by the realm.
Personally, I'm not entirely happy with this rationale myself, but it's clear that that's what Tom wants. However, I think that reintroducing the auto-ban for regions that actually join
enemy realms during time of war is reasonable.
