Years ago I applied a trick I learned from the Associated Press. Back in World War I, the Associated Press suspected that the Hearst newspaper chain was copying their stories from the Russian front, and they began running stories about a fictitious general Nelotsky. When the Hearst newspapers picked up the Nelotsky "story," the AP called them on it, pointing out that the first part of the general's name is just the English word "stolen" spelled in reverse. I used a similar technique on my most plagiarized webpage,
mentioning a college that doesn't actually exist, but has a name from the Greek word for "steal." That finally got one persistent thief to acknowledge that my site was his source.
When I was a kid I had problems with one particular boy always copying my tests in school. I mentioned it to my mum and she suggested I write fake answers in pencil, wait for the boy to copy, and then go back and correct myself in pen.
Similar technique I guess; and he took the hint after a couple of days.
Although some of those ghost streets were simply city projects gone wrong (ran out of money/support), so only some errors on maps are traps.
There is one (somewhat) famous example of a trap, in the placement of two fictitious towns in Michigan, Goblu and Beatosu (this being back in the day of their rivalry).
http://learninfreedom.org/colleges_4_hmsc.html
mentioning a college that doesn't actually exist, but has a name from the Greek word for "steal." That finally got one persistent thief to acknowledge that my site was his source.