Obligatory Leaver Rage

Do people who consistently troll games and leave eventually get their account permanently banned? Decided to play a ranked game and of course someone connected and disconnected all game. His name gave me the impression he was doing it on purpose, and he didn't even get tagged as a leaver at the end of the game. We ended the game with 3 of their towers down and 1/3rd kills more than them. We even aced them at the end of the game but with no ADC there was very little pushing power behind us. Games like this are always so discouraging when I want to start playing ranked.