Not interested in this to be honest.
One thing that I will say is that enabling this by default might peeve a few people who don't want to be known to others.
I think I read on www.majornelson.com that it is enabled by default for all users over 18.
I think it's a silly idea, for the reason you have stated (privacy). Also what is the point of this unless they have expanded the amount of friends you can have on your list (which makes me think an increase in friends list is in the update as well).
rp2000