My daughter's favorite video blogger, i.justine, had this review when she first got Glass:
Around 2:22 she addresses the idea of people being afraid of being recorded.
Around 3:00 is a hilarious "flaw" in the system that her boyfriend figured out.
Around 3:20 she talks again about how obvious it likely is if someone is taking a picture or recording.
Btw, by default, videos are set to stop at 10 seconds unless you reach up and swipe to extend.