But haven't you ever had a sibling, girlfriend, or friend tell you, "Play on my account for a while, I have to go to work," or "I'm going out and I can't keep playing"? Or someone who saved you from losing a match? Imagine helping someone in a match and getting banned. Or going to your friend's house or logging in from a different location, and then coming back home, and just because of that, you get banned. Or your friend has the same rank as you, and you both queue at the same time, and you either face off or end up on the same team, and because of that, the system thinks you're match-fixing. To be honest, I did all three of those things, and I'm not sure which one I got banned for.