What's with Leaverbuster?

I understand getting leaver busted from leaving 3-4+ games in close succession, but what the heck is this? I played a good 20-30 games without leaving at all, then the one game that my internet dies and DC's me, I get leaverbusted and now have to wait 20 mins before a game.

Why is this system so harsh and why does it seem so random?