well i agree w/ the last part of your comment about justice systems in general but...
back when the old forums were up, people would often complain about an unjust ban and get the lyte smite. while it was funny on one level, he'd also give more insight into the way reports work.
for example, it doesn't actually matter if you get 1 or 9 reports in a game. if you get reported beyond a certain threshold, you get a post game message about your behavior. and then when you pass that, you'd get banned. at that point, a random selection of a few of your numerous (and believe me, you have to have been reported in a large proportion of your games) reports gets reviewed. there's also the matter of people trolling with false reports, which lowers the "value" of their report. eventually, their reports won't matter at all.
of course, lyte could just be lying to us about all that. but some of my friends are totally jackasses in game and they've never so much as gotten a chat ban.