AI bullying CS

I've noticed that whenever I have friends or allies amongst CS I get deluged with bullying notifications. I often wonder if the AI is constantly bullying CS (despite only seeing the occasional quest announcement) or whether it just ramps up once I get friends/allies? Anyone know or care to speculate?

I wonder what bonus they get to be able to bully. Sure AIs usually have a large standing army, but very often I do not see them having many units near a CS they bully and as a player I need to have more unit than anyone else near a CS to be able to bully them.