I'm going to use a scenario that I ran into regarding personal information.
I once found some information about a fellow MD'er on a social media site. I knew this person was very particular about their personal information. I didn't choose to add them, or message them, but I did tell them eventually.
Point is, if you find someone's information, don't take liberties with it. Tell them, privately that you stumbled upon it, as they may not know. I have personally had information that I did not voluntarily put out there (I'm looking at you, Rophs), found and acted upon without my app