If a person receives more than a set number of reports in game right now, they will get an action taken against them regardless of whether they actually griefed. This is the reason why many people are complaining about the system currently. I reported many people as an experiment and saw that many got an action taken against them even when they simply did not have a good game and were not griefing. If you picked a hero that your team did not like or made a play which your team did not like you can end up succesfully getting reported without having done any griefing. And it is a myth that action taken can simply mean nothing, an action taken means you receive the same penalty to your behaviour score as that of an abandon (-500).
I personally do not mind a system where griefing is determined based on the number of reports you receive. However, there is a fatal flaw present right now that prevents this system from working as intended and the solution is very simple as well. Remove unlimited reports per person, encourage reporting when necessary by giving a bonus report per successful conviction. It is so simple, when people have unlimited reports, they will report other people for no reason or dubious reasons when they are tilted, and in a system based on the number of reports, it is going to lead to many unfair convictions.