Ok, I didn't understand what you meant before. Now I get were you're coming from.

And I admit it's not as big of a deal with the mod I'm with, since there shouldn't be a huge amount of hordes running into the civilized folks. But I can see the desire to do so in BI, however I wish there was a better way to represent them. Can a faction choose to go horde without losing their city? For example, if they know that a huge army is coming, can they go horde, and run away from them? Probably not...