And I'm not just talking about a training completion.  When a unit is trained they materialize outside the city, but that's not what I'm talking about.  The AI will have like 5 armies in his city, then for no apparent reason will pop 2 of them out.  I pick them off and now the city only has 3 armies making it easier to take.  By the way, if the AI had sent out all 5 armies, he would have beat me.  Similarly, the AI will pop out a half-healed champion by himself who is also easy pickings.  Now that city has militia and 1 hp immobilized champion making it easy to beat.