As part of my profile I request the ability to turn off the receiving requests for things. I'm not trying to sound anti-social here (though I expect I will anyway) but I get several group requests per day from my various 1000+ friends and it's a little tedious to go in and reject them every day. It's totally nothing personal toward those that feel I would be a fun member of their shiny new group, I'm just not presently interested.
Perhaps a small collection of red and green circles indicating things like "Yep, I can receive party invites in game." "Nope, I can't receive group invites." and "Yep, I can receive new friend requests." Individual toggles of anti-social awesomeness?