So...I'm relaxing by the fireplace with my laptop, and what before my wondering eyes should appear, but a new entry on the start screen: "driver update." I click, and get a notification window to update a driver for an Epson printer I definitely don't own and have never used. Wuuuuuttt....??!
I then vaguely remember an Epson printer being on a home network I connected to for a couple days while traveling in the Northwest around New Year's.
Upon opening Control Panel => Devices & Printers, sure enough: the printer had not only installed automatically, it had made itself the default.
Near as I can tell, this unrequested "feature" is disabled via Control Panel => System => Advanced System Settings => "Hardware" tab => Device Installation Settings, although the "ask me every time" option is missing. Is there anything else I should be looking for to ensure it doesn't happen again?