This is as much a "philosophy-of-fiction" question as it is one about whether Lee Child should apologize for a research error in the latest title in his Jack Reacher series.
Some novelists, in our experience, are a bit lazy or careless when it comes to getting all the details right. In Bad Luck and Trouble, for example, maybe Lee Child meant for his characters to be in the area where the El Rancho or Stardust or Westward Ho used to be and he simply got the name wrong when he called it the Riviera. (And did he call it the "low end" of the Strip? We'd call it the high, or north, end.)
On the other hand, maybe in Lee Child's Las Vegas, the Riviera is gone. It's a novel. It's fiction. Which means that anything can be true, even if it's not accurate in real life.
Still, most readers of fiction tend to care about the accuracy of the details conveyed in a novel, especially those with which they themselves are familiar. Take this review of Bad Luck and Trouble from someone who seems to know and obviously cares about Child's descriptions of the novel's main characters as "the best special investigators in the Military Police Corps": " ... after plodding along through half the book, it became painfully obvious to me that Lee Childs knows nothing about the military or those who serve in it. He knows nothing about investigative techniques, nothing about firearms, nothing about police firearms training, nothing about surface-to-air missiles, nothing about the Patriot Act, nothing about terrorists, and nothing about defense contracts or weapons-system procurement."
This reviewer is obviously dismissing Bad Luck and Trouble as contrived and uninformed, and one wonders if Lee Child got a single detail right.
Now, in a writer's defense, the creation of any book is a long, involved, and complex process, but it's especially true for fiction, with its endless research and creative invention and microscopic attention to minutiae and nuance. It's inevitable that someone, somewhere, will find something wrong with the ostensible accuracy of even the most meticulously researched and fact-checked novel. (This is infinitely more true when it comes to modern movies and TV dramas, nearly all of which require at least some willing suspension of disbelief -- and many require near-total suspension.)
Most readers can forgive a novelist for an occasional minor lapse, especially in an otherwise well-conceived and executed story with engaging and sympathetic characters and affirming themes. We've certainly seen our share of mistaken details, uninformed impressions, and all-around wrongheadedness in books about Las Vegas over the decades, but that doesn't mean they all sucked.
To answer your question, though, you'll rarely see a novelist retracting or apologizing for a wrong detail. He probably doesn't want to admit it in public. Besides, where would he do such a thing? On the op-ed page of the local newspaper? In a Letter to the Editor of the Sunday New York Times book review section? In an ad in Publishers Weekly? (Actually, a response to this QoD would be nice.)
If one "comes to light," as you say, the author and publisher might see fit to correct the mistake in a reprint of the book, which is the best-case scenario, and if you care that much about it, you might send him an email and point it out to him. He might even appreciate and acknowledge the information.
