It asks you when you first connect the router. I suspect most people you have contacted are likely to have subconciously (or thoughtlessly) opted in.
If you let me know the URL, I can test from here as I'm on the end of a Sky connection without the opt in blocking so that would confirm if it is that or not.
If you let me know the URL, I can test from here as I'm on the end of a Sky connection without the opt in blocking so that would confirm if it is that or not.