I agree that there should be an opt-out option (other than not installing GFE, tho considering that GFE has always phoned home I don't know if that is that important), yes in an ideal world people should opt-in, the problem is that almost no one does.
Anyone who ever worked on a crash report system knows that opt-in rates are below 10% even for corporate clients.
Heck if you are lucky you get single digit % figures on "send this report" even if the checkbox is ticked by default, the vast majority of people just hit cancel.
The stats are actually pretty darn interesting, especially for image quality vs fps I had a chance to speak to a few reps from NVIDIA once and they told me that as much as PC players bitch and moan about 60fps vsync the vast majority of them would push settings at the expense of smooth(er) framerates even if they have no to very little effect on image quality.