It would probably be easier and cheaper to make hardware for any given person to wear. It's not like they'd have a shortage of volunteers.

I cannot think of something more Big-Brother-like that every other person wearing a 360° camera helmet. Given enough of those, you can visit every place on earth virtually with live data, including everyone in that location. Hooray...

What you're describing sounds like sousveillance, http://en.wikipedia.org/wiki/Sousveillance

Inverse surveillance is arguably a good way to combat authoritarian systems.

That reminds of a short story I read recently:

http://www.ftrain.com/robot_exclusion_protocol.html

I've always wanted to work on long-distance model airplanes for the same purpose - maybe I'll do it in my 20% time if I ever get to work there.