Since I play only in public sessions I have in-game Voice Chat set to 0% volume.
But sometimes I can still hear people talking through speakers.
It seems that after a few games this option resets itself to some default value.
As a workaround I can go to game settings and set Voice Chat to any value, and then back to 0% volume value.
Voice Chat volume setting should remember its value set by user / player.
Voice Chat should not be heard when set to 0% volume value.