Oops; too late. I just got a popup from iPhoto telling me that there was some (unspecified) error in the iPhoto library, and asking if I wanted it repaired. I hit the Repair button, waited a couple of minutes until it said it had finished, and then clicked on an Event that had had the problem. It no longer complained about not being connected to the internet.
So I guess it found whatever the problem was and fixed it itself.
But the question arises: The "Include location information for published items" choice in Preferences is still checked. That phrasing implies that some (all?) of my photos are being published somewhere. I certainly didn't ask it to do that. How might I learn where it's doing this publishing, and maybe stop it? Or does iPhoto just send all the photos somewhere without asking my permission?
This isn't entirely a frivolous concern. Just a few days back, my wife looked at some old photos she'd scanned into iPhoto a couple of years ago. They were from various of her relatives. She noticed that some of them had been labelled with their locations, although there were no cameras back in the 1920s or 1950s that had the ability to label photos that way. Some of them were wrong, but many were correct to within a block or so. And the wrong ones have been changing. She's a bit freaked out by this. How could iPhoto know? Who/What is it sending the photos to, to get them identified in this way? The info couldn't be on her computer; it has to involve someone/something in the outside world.
(One bit of weirdness is the photo that's correctly labelled as being in Organ Pipe Cactus National Monument -- but it's listed as being in Australia, just north of Melbourne. Hmmm ...)