This is not a warning about posting personal information online for your own financial safety.
It’s about contemplating before you post a place of birth for an ancestor if it is speculation. It’s about thinking twice before posting a maiden name for an ancestor online if your only evidence is a gut feeling you had at three in the morning right before the caffeine wore off.
Once a genealogical “fact” gets posted online, it can be impossible to get it removed from all the online trees and other locations where it gets spread. The same thing has always been true about items published in print. A researcher in the 1930s included a maiden name for 18th century Virginia ancestor of mine. Ten years later, she realized the maiden name was wrong. She published a correction in a subsequent publication.
But that first family history she published with the wrong maiden name. It’s the name that appears in about half the online trees that include that relative.
Think before you share genealogical speculation online. And when you are done thinking, think about whether you are really done thinking or not.