They don't do exactly what you said (that I've ever seen). What you may remember hearing is that if you have a spy planted in a city that you attack, and he opens the gate, then the enemy doesn't get a deployment phase - their troops begin the battle randomly scattered about the city, to represent them being taken by surprise. This can be wonderfully convenient, as you can often just pour troops through the open front gate and establish yourself inside the enemy walls before he can even do anything about it. If you've both got sizable armies the fighting that ensues in the streets can be absolutely insane though!Originally Posted by Chosun
It only took one time of this happening to me before I decided border towns had to have spies to kick the enemy ones out - it REALLY messes with your defense plan if you don't get to deploy your troops.
Hope that helps.
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