population doubles when homeworld rebels !

[Slick]

Another neat thing is that the new empire has all the same techs as the original empire. So you can get lots of new techs if you get them to surrender, which is easy because your score is much higher.

Slick.

[Gozra]

My guess is when your rebel planet becomes an AI it also gets to have AI advantages. And maybe an AI advantage is a huge population. Which is an Advantage. I had this happen in a game once it was a bright spot on the road to ultimate destruction. I never surrendered as I did have som mines still active on the map somewhere but I did concede the game.