I'd like to second this, however I would say it's required not just handy. The racist rubbish we have to listen to as players before almost every BR round is outrageous and must be addressed

bit.ly/1Hmcwzy

Well, BI can't do much about what other players say...

hence the need for a MUTE ALL function so we don't have to listen to it

I would love this feature too. To be able to toggle to mute all players with a keybind, in those moments when you need to listen for footsteps and everybody is going off on side chat.