She informed the city, archeologists came in and shut the place for a year.
She was curious but could not do anything.
When she finally got her place back, she discovered an artezian spring in the basement but did not tell anybody and had a great source of water.
Such discoveries are not always fun.
This should be seen as a risk for anyone buying properties this old, just like any other risk in business. I wouldn't be surprised if there's insurance for this.
The problem here is that the place was shut down for a year with maybe two weeks of work. This is European bureaucracy, not preservation of historic artefacts.
As far as insurance goes, it just reduces the variance. Folks who buy the insurance will take short-cuts elsewhere because money spent one place is money that can't be spent another.
And, if you're tempted to respond with "but it wouldn't cost much", my response is "then there's no reason why you shouldn't pay that cost."
And yes, I have a 120 year-old house that I'm keeping as authentic as reasonable. (I do want electricity and central heat.)
What have you preserved with your money?
The landowners mostly stay quiet for two reasons: One, who knows what the county, state, and the Chumash bands will want to do this time? Second (and far more importantly), if officials are informed it's essentially certain the locations will eventually leak and open the sites up to thieves and vandals. My understanding is that the sites have been made available to researchers under a covenant to not reveal the locations.
To the second point, one only need refer to the tragedy of Painted Rock:
https://en.wikipedia.org/wiki/Painted_Rock_(San_Luis_Obispo_...
I'm sure if she shared the news about the "artezian" (artisanal?) spring it would have added a bunch of fun for the archeologists, the city, historians, family who are/were related to the house (if they found out) and more, while maybe not being so fun for your entrepreneur friend.
Artesian: it refers to groundwater under pressure.