IMHO: people are idiots. Your phone says: "Application «blablabla» would like to use your location", and they press "yes" without reading the message. And then they're so afraid about stuff like "map marking/monitoring". + most of people post on public so much info, that you don't have to hack anything, just read what humans show to everyone.
People are stupid, and there is nothing new.

P.S. from 50 millions people who live in US, do you know how hard (and pointless) look for specific person? First you need to get (in)famous enough so someone would be interested in you.