Remember when the book was written. She might have had a copy of the VHS, though I wouldn't count on it. More likely she had the script, and her memory (if any) of the episode.
That's a good point, though I'm surprised she wouldn't have had something to verify who was on the Bozeman bridge. Carey has written other novels and likely has contacts within the Trek universe who could help find a video of the episode in question. --Sran
^To be fair, it's not as if continuity errors were unheard of in older novels, before Memory Alpha and Netflix made it easier to check references. There are some doozies here and there. Web of the Romulans and Double, Double are both explicitly placed right before or after first-season episodes, and yet have Chekov as navigator and refer to "The Enterprise Incident" as a past event. DS9: Warchild assumes that the runabouts are Cardassian-made craft that came with the station. Corona suggests that Spock is nearing his eighties in the TOS era, even though his human mother was clearly younger than that. And so on.
That's true. I suppose I've introduced my own small continuity error into the Trek fan fiction universe with the creation of a Romulan character on whom my username is based. But I digress... --Sran