I was using a Rand McNally map of San Francisco once which showed an Alley. . . and it simply did not exist. I called to report the error. . . and was informed they were quite well aware of that non-existent alley and was told they put it there deliberately. It's a deliberate error, I was told.
Rand McNally maps used to include non-existent streets and alleys on their maps as proof that another map maker had infringed their copyrights in their maps. . . On national and world maps there will be a non-existent river, mountain, city or town somewhere. . . and AT&T Yellow and White pages includes non-existent businesses and names/phone numbers for the same purpose. If those streets, alleys, rivers, cities, mountains, businesses, and names or phones numbers appear in someone else's products the publisher of the original has prima facie proof of copyright infringement and the copyright owner could sue and win!
Rand McNally actually wanted people to know these "ringer streets" existed. . . but would not let people know where they all were because the purpose was to discourage counterfeiting of their products! If you found one and called, they'd explained the fakes.
That's actually pretty common in the map-making world, and is not, by any means unique to Rand McNally.
These days I don't really see the point, since the vast majority of data for street maps is available for free download from public domain sources derived from government information.