I mentioned this in one of the dev journals just now, but I figured i'd put it in its own post too.
Right now, one incentive for not rage quitting is that you won't be able to get your favor points for playing out the game to its finish. I'm still seeing a ton of rage quits though. I don't think it would be a bad idea for a person who rage quits to lose some of their previously earned favor points.
They do something kinda like this in halo 3 on xbox live. In halo 3, if you win a game u get an "experience point". If you lose, you dont get anything. If you disconnect from a game before it's over, you actually lose a point. Also, when you try to quit a game, the "leave game button" doesn't say something nice like "are you sure you want to leave? (yes or no)" it says something along the lines of "Are you sure you want to leave? (Yes, I'm a quitter. Penalize me. or No, I never give up on my team)".
I'm not sure if halo has some way of differentiating between disconnects and rage quits, or if they just decided to make the penalty small enough to where nobody would really get too upset if they got disconnected and got the exp penalty.
I'm not proposing an enormous penalty, maybe just a small one like 10 to 25 points deducted.