Yes, but I believe some of the AI scripts are predictable. For example, in every war i've been in so far the AI has always attempted to send a pillaging unit - usually horse archer - to destroy my improvements. This is a realistic, good, and useful action for the computer to do but is usually predictable.
As well, I suspect some degree of cheating when the AI does any attacks of opportunity against weaker cities. I've had the AI simply walk past my fortified border city and try to attack a city with a weaker garrison it could not have possibly seen.
I'm not sure how easy it is to manipulate the AI yet, although I bet shared religion will have a major part in controlling alliances.