In the case above, "someone's face" was my face. And the drone was most certainly following it. Frankly, it was a little unsettling.
While there are other drones capable of following a subject autonomously, like the Lily Camera and the Airdog, most require the person being followed to wear an accessory (a GPS wristband, for example). The Hover Camera requires no such help. It follows your face, which, to reiterate, is unsettling. It is not hard to imagine a dystopian future in which — after a few bad decisions — we are begging for mercy from the next-generation Hover Cameras that have just successfully and savagely hunted us down.