After I finished a game with Rabid, he left the game, and before I noticed that, I requested a rematch. The result was that I ended up in a game with Lord Rattington. Clearly not what I wanted (and annoying if resigning would affect my rating).
In the same subject, my opponent ask for a rematch while I was always on the game window after the game. The new game start without asking me if I want or not.
This will change in the near future.
Right now, the host of the table can start a new game if he feels like it.
In the future the new game will start if all players agreed to start it.