This icon should be visible on agent icon to let other player know that other 3-2 players are in a party. It is often seen in lower Elo that a party of 3 often play their own game without communicating with other player. When asking the reason for that, they get aggressive and they gang up on you. This leads to throwing the game. If I know that it is a party of non cooperative player, I would shut up and just move on without any confrontation. What are your thoughts on this?