I've been thinking about the multiplayer aspects of the game lately and how they'll work, and I must say I am a bit worried about possible abusive usage of the game's save system in order to get an unfair advantage. That, and simply modding the game. With just a few changes to the game's code, you can get richer or more popular, and I imagine the same method could possibly apply to influence, making it much easier to snatch idols from other players' groups.
I've never done that myself, and only use the save game system the regular way, but I can see how it can be used to get better idols on your auditions.