What if Facebook was actually called Policebook?

Apparently, a serial murderer and rapist was identified by the police when they used a DNA database (called GEDmatch, which appears to be a site meant for helping people find their relatives) to which he had voluntarily provided his DNA data. Science has an interview with Yaniv Erlich, a Columbia University geneticist, who had alerted to possible uses of a site such as GEDmatch in 2014.

An excerpt where Erlich makes a key point:

Q: There’s a lot of concern about privacy being compromised here, but people voluntarily put their data into GEDmatch.

A: It's not like people fully understand the consequences of putting their DNA into a public database. They think, “So many people use the website, so it’s OK.” Or: “Oh, it’s a website for genealogy.” What if it was called Police Genealogy? People wouldn’t do it. We don’t think about everything. We think about the most likely thing. [Bold emphasis added]