We as the players can pay bandits and willing lords for safe passage, a guarantee that neither party will attack each other for a couple of days. This should also apply to AI lords as well. In a field battle where we greatly outnumber but especially in a siege, if an AI lord is stuck in a town with his 80 troops against an unwinnable force of 1000 men, he should ask for a safe passage for a fee. Moreover, if we siege a town (not a castle) which has little to no garrison and low militia count compared to the sieging party, we should be able to negotiate with the defending commander (can be a lord or a no-name rando character) for their surrender with the guarantee that our army will not sack the city (so only show mercy option will be available, or even we get the town and the option for pillaging the settlement won't show up). If we were able to do this even before the siege camp is set up, it would greatly decrease the amount of unnecessary grind in the late game where we have to take back the settlement we lost 5 seconds ago.