Possibly a bug with the AI/spy routine though. I've had my capitol (edge of my land so vulnerable) assaulted numerous times, ~1/2-3/4 of the time, the enemy had a spy, so no deploy.

However, everytime they assaulted as if there were no spy. I got the vocal message at battles start about some treacherous dog opening the gates, yet the enemy hits the gates with rams, uses ladders and towers. I almost wish I could point out to the prisoners that if they had only tried the handle, the front door was unlocked all along. :)