Lillian Virginia Mountweazel is a copyright trap. She's a made-up person who was included in the 1975 edition of the New Columbia Encyclopedia so that, should Mountweazel show up in any other reference book, then the New Columbia would be able to prove plagiarism.
If the idea of filthy lies in reference books fills you with righteous indignation, don't write that scathing letter to New Columbia just yet.
Mountweazeling, as I've just decided we're going to call it, is a tradition that goes back a very long way.
The tradition probably begins with maps, which have included false entries, sometimes called paper towns, for centuries. One such town was Agloe, New York, first hidden in Esso road maps by mapmakers Otto G. Lindberg and Ernest Alpers in the early '30s. The town, its name an anagram for the initials of the mapmakers, began appearing on other maps in the 1940s. Esso threatened to sue another mapmaker in 1952, only to discover that Agloe had become a real place when they weren't looking - someone had erected the Agloe General Store at the spot, prompting a county administrator to declare Agloe a real town. The general store went out of business some years ago, and the town of Agloe disappeared along with it.
Fred L Worth was tipped off that Trivial Pursuit had borrowed facts from several trivia books he'd written when a clue repeated his false claim that Columbo's first name was Phillip. It turned out that Trivia Pursuit had used Worth's books so liberally that they'd copied over some of his typos. Worth lost the lawsuit he filed against them based on Trivial Pursuit's claim that copying verbatim was just "doing research."
Information for this post came from The Allusionist, Mental Floss, The New Yorker, and Omnictionary.