You can already opt out now. When you sign with any major ISP the first question it asks you on connection is, basically, parental controls, yes or no. You say

You can already opt out now. When you sign with any major ISP the first question it asks you on connection is, basically, parental controls, yes or no. You say no and get on with your life. The single and only thing that Sky have done today, is changing that "If you don't answer, we'll assume no (filtering)" to "If you don't answer, we'll assume yes."