No. Automatic Downloads are turned Off by default.
No, it isn't. Apparently you're told to turn it on during setup (it's "recommended" or something) and so it doesn't default to either off or on, you're forced to decide. Which means that:
If it is setup otherwise on your devices, you turned it on.
Is technically true. But only technically.
Because there are definitely people out there who have automatic updates on and didn't know that their phones could even do that. They complained loudly enough that this article exists.
So either someone else turned it on for them, or they missed the part during setup where they could turn it off. Or more likely failed to understand what they were asked during setup and turned on a feature that they had no intention of ever using, since it's only useful in a very bizarre set of circumstances.