How could you use a copyright trap in other creative work, like writing and photography? It’s not like a watermark for photos but a way to prove the work is your own from something only you would know was an error.
The more likely story, though, is that Argleton was an example of a copyright trap, which cartographers have long used to catch would-be thieves from stealing their hard work. In this case, either Google was laying the bait for a competitor (hey, Bing?) or the mystery town was inserted in analog form long ago by Tele Atlas, the Netherlands-based company that supplied Google Maps with its initial framework.