Android does this too. About a month ago I flashed a new ROM and forgot to disable GPS again. One afternoon it notified me that it was 'time to go to work' and plotted a route to my sexfriend's apartment.
That is amazing. I forsee these things getting people in trouble in the future. "You said you were at Danny's house? Did he move in the strip club on the corner of Dirty and 157th? Because that's where your phone said you were."
I can't find the article through surface level searching, but I remember reading something that showed that this is already the case. Using Apple's Find My Friends App, a wife found out her spouse was cheating on her. He had forgotten about the app, and it revealed that he was at the woman's house. I just try to steer clear from location-based apps. Except for Ingress...that game is so cool, especially for an on-the-go Campus Kid like me.