Why would a 4 man report one of their own?
Also I believe that 4 people reporting you in one game is no worse then 1 reporting you.
Also it takes being reported lots and lots, upwards 20% of your games, to end up in tribunal at all.
Then the tribunal picks random cases where you have been reported to show.
Then judged like me do indeed read the chat to see if YOU being the person reported were a problem.
So if its just one false report, it wont hurt you much or at all. If that is the straw that breaks the camels back and gets you into tribunal, you were already extremely close.