Enter use*
What it seems like you're fishing for is someone who sees the word in a dictionary, learns it from the dictionary, and then accidentally puts in the text of a book, article, or whatnot (as opposed to stealing it for a reference work that specifically collects all words or is about unusual words, or "joining in" on the hoax for humor or "easter egg" purposes).
I also assume you mean intentional hoaxes, not mistakes.
Unfortunately, I can't prove a definitive kind of cause and effect like you're hoping. I can give a case where a hoax word was known among word-enthusiasts as unusual, but later called out and made famous amongst the public, and only after that was the word used in regular text.
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The earliest case where I know a dictionary made a hoax, rather than just a mistake, is the word zzxjoanw.
It appears in the Music Lovers Encyclopedia of 1903 in a section entitled A Pronouncing and Defining Dictionary of Musical Terms and Instruments.
Here is the same entry from the 1913 edition
Zzxjoanw is given a pronunciation of "shaw", is identified of as Maori origin, and defined as 1. Drum 2. Fife 3. Conclusion.
Dmitri Shaw later discusses the word in his 1965 book Language on vacation and clearly does not spot its intended hoax-ish-ness. I'll give the parts before and after for context:
Starting on words beginning with a double Z, we note that H.L. Mencken, in one of his books on the American language, cites an interesting feminine given name found somewhere in the United States: ZZELLE.
Onward, ever onward! The Music Lovers' Encyclopedia, compiled by Rupert Hughes, revised by Deems Taylor and Russel Kerr, and published in 1954, presents us with one of the most unbelievable, one of the most intriguing letter combinations ever to claim recognition as a word: ZZXJOANW. This spectacular word is so versatile that it possesses not merely one, but three different, meanings: (a) drum; (b) fife; (c) conclusion. The term is of Maori origin.
The Polish language goes a step further, with verbs like ZZYMAC ("to shrink" or "to shrivel") and ZZYNAC ("to mow off").
The word also was stolen wholesale for the 1974 Mrs. Byrne's Dictionary (which proposed a different pronunciation from "shaw"). The word wasn't called out until the late 70s in Word Ways: The Journal of Recreational Linguistics.
He probably intended the hoax to be obvious, but he reckoned without logologists, made credulous by experience with other outlandish words. Whatever his motives, I, for one, feel betrayed. I thought that "zzxjoanw" was the perfect example of an amazing but real word; there is no other one cockeyed enough to replace it. (A philosophico-logological question: does a hoax word gain legitimacy from 42 years unchallenged appearance in a standard reference, and citation elsewhere? An error, no, but ' zzxjoanw' approaches the status of a successful coinage -- successful, at least, among logologists.)
Incidentally, the Maori alphabet only uses the letters
a, e, h, i, k, m, n, o, p, r, t, u, w, ng, wh
and all words in the language end in a vowel, so even the most cursory of research checks would have revealed the fakery.
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Because it was it was one of the better-known hoaxes, and authors do tend to obsess about words enough to know these things, when a word is used later it's hard to tell if it's meant as an in-joke or not. David Brin included the word in his 1990 novel Earth. The novel is about a microscopic black hole falling within the Earth (like The Krone Experiment from four years before, I guess everyone was worried about black holes in the 80s):
Auntie Kapur tapped a steady beat on a miniature ceremonial drum -- which some called a zzxjoanw -- while making fatidic statements about amorous goddesses and other superstitious nonsense.
"... You reach deep within Pele's hidden places, touching Her secrets. She would not permit this of just any man. You are honored, nephew."
Is this really David Brin being "fooled"? While he hasn't commented on it any interview I've found, it seems an intentional reference.
In Batman 3D by John Byrne from the same year, there's a receipt mentioning a delivery of a "zzxjoanw" to the victim of a murder. Batman uses this to link the receipt to Hardiman Twine (the victim of a murder).
There's no reason Jim Gordon would know such a thing, of course... but "zzzjoanw" happens to be the proper name of a kind of Maori drum. Something Hardiman Twine would have been delighted to add to his collection...
Perhaps this was the author getting caught by the hoax? But: the Riddler is a major enemy in the comic, and the general theme is a lot of riddling (it starts with the Penguin taping a confession to the murder and sending it to the police); the context strikes me as an intentional reference as opposed to not knowing it's a fake musical instrument. Again, I don't know of this being brought up in an interview, so it's hard to know for sure.
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You'll notice I still haven't quite got exactly your question since you asked about copyright traps specifically. The most significant "real" copyright trap I know of is The Trivia Encyclopedia, which put the fictional detective Columbo's first name as "Philip" (in reality, his first name is never given). This piece of trivia later showed up in Trivial Pursuit and ended in a lawsuit:
Worth lost the suit; quoting from the decision:
Factual works receive distinct treatment from fictional works under copyright law. Landsberg, 736 F.2d at 488. Indeed, facts, like ideas, are never protected by copyright law. Cooling Sys., 777 F.2d at 491; see also 17 U.S.C. § 102(b) (1982) (expressly excluding discoveries from the scope of copyright protection). Because authors who wish to express ideas in factual works are usually confined to a "narrow range of expression ..., similarity of expression may have to amount to verbatim reproduction or very close paraphrasing before a factual work will be deemed infringed."
This means it is very doubtful a dictionary-word-copyright trap would work applied to the law. I only know of one dictionary trap which later claimed to be for copyright purposes (as opposed to a map, encyclopedia, etc). 2001's New Oxford American Dictionary included "esquivalience" reportedly as a copyright trap, but even though it appeared on the commercial site dictionary.com, no lawsuit resulted.
Encyclopedia traps tend to be more substantial (and more likely to cause "verbatim reproduction" as mentioned by the court decision). The New Columbia Encyclopedia included Lillian Virginia Mountweazel, a fountain designer/photographer who died at the age of 31 at an explosion while working for Combustibles magazine. Richard Steins, who worked on the encyclopedia, explained:
It was an old tradition in encyclopedias to put in a fake entry to protect your copyright. If someone copied Lillian, then we’d know they’d stolen from us.
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Alford, H. (22 Aug 2005). Not a Word. The New Yorker.
Borgmann, D. A. (1977). At the Outer Limits. Word Ways, 10(2), 18.
Brin, D. (1990). Earth. Bantam.
Cohen, P. M. (1976). What's the Good Word?. Word Ways, 9(4), 2.
Grant, J. (1981). Kickshaws. Word Ways, 14(4), 16.