I've gotten about 1,000 false reports since the beginning of this season.
And have not once been chat or ranked restricted. Keep false reporting me, kids. Nothing will ever come out of it. I've internalized the supakawaii-do-no-harm-unto-others-stop-hurting-my-feelings attitude that Riot wants me to have.
Moreover, I can attest to the fact that each case is individually assessed for accuracy, and not automated as many people have claimed. There have been times where I've received multiple false reports in succession (by many teammates, in many games in a row), yet, Riot checked the chat logs and saw that I was innocent.