Bait and switch. Release a great service with sane privacy settings and policies, make any privacy-sensitive settings opt-in at first, get people using it and depending on it. Switch it to opt-out but no one notices or cares because they're already on the hook and it's a media darling. Then change the privacy settings and policies to something nefarious while leaving it opt-out. Even if the media brings up the new privacy issues, only the folks who are already privacy-conscious will notice or care, and they probably weren't using the service anyway.
See Spotify for a very recent example of this process.
How is making a feature (that is opt-in) good enough to get people to opt-in a bad thing here?