The only time you've played with that graves in 50 games was your last game. Stop lying to make your complaints look believable.
I don't think you understand.
Leavebuster handles leaves. Leavebuster is not influenced very much by the reporting system, since it's next to impossible to know why someone leaves a game without some sort of admittance. A leave may or may not be intentional without a confession, so the leavebuster gives players a little lee-way to account for unintentional leaves.
If someone admits to be leaving the game intentionally, you can report them for poor behavior. Even if we assume there's a system that could be implemented that would punish immediately after a leave, it wouldn't prevent leaves.