... Eh. On one hand, I do dislike the one asshat who leaves his mic on when he's using TV speakers, not even talking, and has a goddamned crying baby in the background that he should probably go calm down. On the other, I feel like party chat has sort of killed the spirit of online gaming. Part of what I always liked about playing games online is that while you're playing you can still interact with other people, socializing and messing around even if you've never met them before the lobby. That still happens a bit, sure. And in some games, like in my experience the Halo series, you still do manage to see a decent mic turnout in game chat. But in a lot of them, well, everyone else might as well be bots. The only interaction you could potentially have ends up being hatemail or the occasional complement for something godly you did; meanwhile, if you were actually on voice chat with each other you could have seen that reaction in real time and had a lot more fun with it. You're basically asking to play an online game alone. That's sort of dumb.

Better yet, mute as default, add if you want.

When I see that I think "OMG Someone not in party chat, YES... Social activity and not boring dead silence" Then I'll proceed to make a friend or an enemy Hopefully a good guy that I can play a few matches with