If you swear that a word in a dictionary or a spot on a map just can’t be right, you might be correct. Turns out that cartographers and lexicographers make intentional mistakes to thwart people who would steal their work.
The idea, as explained in a Wikipedia article, is that someone who violates copyright would unknowingly duplicate the error, thus proving they had broken then law:
By including a trivial piece of false information in a larger work, it is far easier to demonstrate that someone has plagiarized that work: they will presumably copy the fictitious entry along with other articles.
Another great resource for this is a Straight Dope column on trap streets.
So what’s the message? Reference works aren’t perfect. In fact, they are imperfect on purpose, as a way to prove that they are revered.
You guessed it: Failure is the secret to success!