Well, it was a pain to see people ignoring others that could have easily been resurrected or helped in another way. But that was during beta (where most people were busy getting to know the game) and only rarely.
Occasionally it might hurt my experience, but not too much. I voted yes, though, because not helping just sucks and the game simply invites the player to play as a team. It's so easy to team up (just go to somebody and do what he does, that's it) which is why I consider it to be incomprehensible to not do it (or rather: to avoid it).