My aunt was a genealogist, professionally and for her DAR chapter. She was a snob, but also very honest about her work. People would get mad if she found that their ‘true’ ancestor, according to actual records in old churches, graveyards, etc., was some common menial laborer instead of the fancy person they had assumed...
Years ago I read about a late-19th c defrocked monk (this is another story from Failing Memory Lane, btw) who took to doing family trees. There was a big uptick in interest at that time, a lot of the surname books were done circa 1890.
Anyway, to satisfy his customer, he invented a king of France, and continued to add invented children of of the imaginary ruler, none of whom succeeded their father. In the mid- to late- 20th century, people are still discovering that scam as they retrace the family tree inherited from some earlier relative of theirs. :^)
When our local library had free access to much of the Ancestry resources, I found and read the application stuff filled out by a known cousin (I never met her, and she lived in a more easterly state) to join the DAR, about a hundred years ago. My info matched hers, so that was cool, I didn’t know she’d done that.
Running into a posh ancestor wasn’t something I expected, I figured my modest research would eventually run out of archival records for each line, and about the only thing I’d ever know about these was some or most of their vital info, because we’ve been from the po’ side of town since before there was a town.
When it happened, wowee. But again, just because they’ve got a written pedigree (not to mention references and info in dusty old history books) doesn’t mean they weren’t crawling all over everything that moved. :^)