They're just going to do a classical boil-the-frog operation:
Step 1: Make it opt-in and present it as the new cool thing.
Step 2: Make it opt-out, and if the users opts out, show a scary warning about how the cool thing won't work anymore.
Step 3: Silently opt-in, and hide the opt-out option deeply in a settings menu.
Step 4: Silently opt-in, remove opt-out, but it still works with a registry hack. Microsoft apologists will still thinks it's cool because "just use this simple registry hack bro".
Step 5: Remove opt-out alltogether, and silently opt-in everyone who had previously opted out.