I encountered one writer claiming their work was Genre A disguised as Genre B.
The thing is, people who read steampunk want to read steampunk. Readers of book club fiction are looking for book club fiction. Crossovers are okay within reason (though beginning authors tend to throw all the genres into their book thinking it makes it better and more original when this is not the case). But “disguising” a book as another genre won’t help your readers.
What concerns me most is there’s a definite value judgment in that phrase. This query is clearly from a Genre B writer, but for some reason they believe Genre A is better. They’re trying to write Genre B in the style of Genre A. But genres exist so readers can have basic expectations–recognizing what’s weird, what’s scary, or what’s quotidian to their characters, and what kind of pace they can anticipate.
Don’t be ashamed of the genre you write. Sometimes our education can make us think literary books are somehow better books, or science fiction is better than fantasy, etc. But a book is good if it impacts its readers–no matter the genre.