I used to blindly rely on google maps until it misdirected me on my way to Redwood National Park. It led me to a house in the mountains that had a sign saying something like - google maps has misdirected you and there is no path through this house to the Redwood national park. It was a place where even the cellphone did not work. This happened ~6 years ago and hopefully google fixed it by now.
Similar story. Was in a caravan with friends on a road trip and apple maps had us going onto a dirt road to save time. We go overlanding a lot, so dirt roads aren't weird, but we decided to stop and double check before proceeding too far on the road.
About a minute later, a border control agent pulls up next to us and starts with the standard interrogation. Turns out, apple maps had been telling people to use a dirt road to circumvent a border control checkpoint - which according to the officer was a felony. We proceeded back onto the pavement and through the checkpoint where they waved us through. The dirt road wouldn't have been faster at all, so it was puzzling why it was giving those directions.
One possibility that occurs to me is that various people might have reported the border checkpoint to Apple Maps as a blockage in the past, in order to get it to give them a route around it.
Not that this absolves Apple, of course, since they should absolutely be checking these things better.
They probably haven't and even if they have there's probably some other bogus data in there.
A lot of these maps will have a couple 'tells' added, things that don't really exist to say that if a set of things was copied it came from a different place.
Really sucks when you happen to need to go somewhere you haven't been before, that's actually where that place is next to. Yes, that does happen. E.G. when relatives and friends live on private roads in the middle of nowhere.
Yep “paper cities” is what to google if you’re interested. We have a “paper bus route” in my neighborhood at bus stops that were removed 10 years ago, that serve the same purpose, as far as I can tell.