No. Muting people and not typing in chat is considered neutral behavior, I believe, so it won't get you in trouble. It's a bit extreme but I guess if you're that unable or unwilling to control your temper you may as well.
You can still get reports for refusing to communicate though. That's the grey area you're talking about I guess. Chat isn't required, but if you aren't being a team player that's different. Just use your own judgement and try to be logical about it. I sincerely doubt people get banned for refusing to communicate as the sole reason.
Note: Be careful in post game screen. Muting doesn't prevent you from seeing what people say there, and I'd say it's pretty common that a lot of people get reported due to being toxic after the game is over, even without having said or done anything wrong the entire game. The button is right there after all.