I have seen many of these type events.
They never seem to mean much, though, because they (the AI's) always seem to act the same way as before. They'll still attack anyone that they seem to have the advantage over.
They can mean quite a lot in terms of diplomacy, though. In a DA game full of evil races, when the Altarians had this "ethical reversal" event, it shook things up a lot. I once lost a game as the Drengin (which I admittedly wasn't taking seriously) when my powerful Korx friends suddenly became good and our relations slowly downgraded. Eventually they declared war and that was that.
I also, fairly recently, saw an event I'd never seen before where the ambassador of one race accidentally insults another race and they go to war. It said that having more espionage could have prevented this event, which seems to indicate that the AI doesn't spend as much on it as it seems.
In terms of mega events, though, I get the same ones over and over.
BTW, on a slightly related note, does anyone know whether the "Random Event Frequency" option in TOA affects normal events, mega events, or both? I haven't really played TOA.
