When are leavers getting bans?

Last two games.

First game, adc's support dies once, not really a spectacular death. ADC qq's he's done and sits at base all game. Me and top try hard to carry but 4v too much. Lost.

Second game. Jungle feeds my lane 3 times, playing REALLY poorly, then quits. Everyone else on my team feeds hard. I dont die, get a few kills. Still lost. Btw this afk'r has 3 leaves in his last 20 games.

In danger of being demoted through no fault of my own. Leavers need bans, people on their teams need loss prevention.