There is no more opting out, only opting in.
As it should have been from the start... however good customer service would suggest a confirmation response - even if just a copy/paste standard one - would have been a good PR move in the hope of showing willing, and in restoring some integrity to the project, should at some time in the future any of us decide that such tracking may be beneficial to our style of gameplay.
In principle, I see this as a potentially very useful tool - for those who wish to keep track of how much time they spend with friends, or for perhaps other reasons further down the development track that haven't been coded yet.
I still find it hard to believe that this backlash wasn't foreseen. It's like someone giving you an item marked "Nuclear Bomb", which when you rez it, right clicking gives you an option to "Bring down entire grid", then showing surprise when you get suddenly logged out.
Lewis