Nullifying the game when someone leaves

If you agree with me awesome, if you don't I don't care, these are just my thoughts. After playing many ranked games and losing many ranked games because someone decides to run straight down their lane feed the other team and leave is quite frustrating. I propose that if a player leaves for more than say 4-5 minutes which is much longer than any normal dc and long enough to disrupt the outcome of the game before a given time say 15-20 minutes to nullify that round and not have it affect either team as a win or a loss cause it's an unfair loss for one team and a cheap dishonest win for the other team. The player who leaves should still get punished for leaving the game. Also, all the time frames are tentative it's just an idea which also prevents people from leaving late in the game to nullify it for their teammates. It is simply frustrating to be playing, losing, and ultimately wasting time when someone decides to leave early on.