Yeah, it's pretty dumb. Not sure if there are any mods that fix it (I only play Diplomacy, and it doesn't). It doesn't make sense to me, since you can abandon a siege and flee from an opposing force, but you can't abandon a sacking?
Actually, I think it would be pretty nifty to have a "sack" option, where you just wreck the village but don't get (m)any rewards for doing so, other than a burned, useless village.
There's source code to change this that I've written. It can be found in the "Module System Code" link in my sig. It isn't an easy text tweak as the code is in different places, so there's no .TXT edit version, unfortunately.
Okay imagine if you have 10 troops, killed all farmers and loot. When you see a party of army you flee. Thats dumb. If you get defeated then start all over again! Whats to loose. 10 troops? I lost 120 troops and I had to rebuild.
Actually, a raiding party of ten should have every opportunity to flee from a large (and usually slow-moving) army of 100, especially given the open nature of village borders. Not having that option detracts from realism as I see it. If you did flee you'd return to the world map where the chase would actually start. If they are faster than you there, they have you for good.
Gear, a large part of your cash, and a lot of valuable time being a prisoner and after that needing to cruise all over Calradia to find all your companions again who ofcourse all hang out in taverns in enemy towns, where you need to sneak in and then get unlucky and get captured again.