Instructions
Search for objects and other small locations on the outskirts of the village that have been attacked. This can sometimes happen when an opposing guild is simply passing through an area, but this is the first step that has to occur for an area to eventually flip to an opposing force.
Search for non-player characters (NPC) that have been killed in the villages near the Keep of the controlled zone. Whenever an opposing force begins attacking NPC in villages, it is almost always in an attempt to draw forces from the Keep, which can leave it vulnerable to a siege attack.
Station your character in the area of a controlled Keep. A Keep is the final object that must be captured to take a zone. When its Keep comes under attack, you will be able to tell a zone is about to flip.