More than once I found that in battles, certain group hold position near a fight for no reason, letting them be able to be sniped from close range or just stalling the fight for no reason. In one instance, their enemy was a line of archers just 10 meters away, but they held position until they were all killed by arrows in the span of a few minutes.
EDIT: If you try to buy supplies or cattle from an enemy village by talking to the elder directly, even though he says "No way!", you'll still be able to.
EDIT2: The option to exclude certain companions from tournaments doesn't seem to work.