Here's a youtube video of people's reactions to being filmed by a stranger. It's fascinating to watch. I'm not sure that Google Glass will really offer that much to change the already omnipresent recording going on around us, but people's obvious and seemingly invariable discomfort about being filmed is interesting.
Sidenote: Does anyone know what laws govern this kind of activity? Is it legal to film anything in public? What about taking photos; are the laws different regarding those?