Everyone saying that 1 person is all it takes: yes, that can be the case if it is severe enough an offense.
However, multiple people reporting you counts against you for every report generated. Riot can talk out their ass all they want, and anyone that believes that shite is just being willfully ignorant.
I just got a chat restriction because apparently you can't swear in a game anymore even though there's a built in censor for that. Totally didn't deserve the restriction. And what's worse, is that my team was harassing me and flaming me the ENTIRE fucking game. But did my reports do anything? NO. I'm the one that gets fucking punished.
This game is still absolute fucking garbage. Been away for almost 10 months and come back to see still shit 'penal' system. 90% of the time wrong people get punished, too, just because their team is a bunch of douchebags.
I don't see it as toxic to ask for reports and I have never reported anyone for that. You wanna ask for something? Go right the fck ahead. It's up to each person to decide to fulfill that request.