Don't know why it took so long for me to figure it out. Anyway, it's obvious that game disks come with a sub-routine so that the manufacturer can go online with YOUR computer.
I recently dusted off an old "Torchlight" (the first, not Steam's "Torchlight 2") disk and installed it. When I began to play, I noticed that gameplay was slightly different from when I'd last played five years ago. Some of the changes were minor, others rather drastic. I then looked at the version number: v. 1.13. The disk itself read "v.1.0." I was not prompted for an update, nor did I knowingly go online.
So be aware: even if you aren't using your browser, Big Brother IS watching. I don't believe that pre-Y2K disks had this capability, but back then about the only time you used the internet in conjunction with a game was to register as the owner, or were playing a (yuck!) multiplayer game.