I read only an excerpt from David Brin's 1998 nonfiction book The Transparent Society, but the gist of its argument as I understood it was this:
The authorities are going to soon have more or less total surveillance. Given that, it is good for society if citizens also have more or less total surveillance.
(If you disagree with that statement, don't bash Brin for it; I'm summarizing/oversimplifying an idea I read ten-plus years ago, so my version of it may be only distantly related to what Brin actually wrote.)
There are all sorts of arguments to be made against that idea. (See Schneier's counterargument, for example, though see also Brin's rebuttal.) But I'm inclined to believe that, in broad outline, it's true. Authority has access to more and more, and better and better, surveillance over time; citizen countersurveillance of authority (what Brin calls “sousveillance,” if I understand right) is, or at least can be, an effective tool in keeping that from becoming a major problem.
But of course the surveillance doesn't just flow across power boundaries. Once the tools are available, a whole lot of what people will be observing and recording will be each other.
With all of that for background, enter Google Glass. (Which I personally am really excited about, btw; I plan to get it as soon as it's available to the general public. I will, of course, turn it off or remove it whenever I'm with friends who are bothered by it, just as I refrain from taking photos of friends who don't like to be photographed; and I won't post stuff publicly without permission, just as I don't now.)
Whether or not Glass itself takes off, it seems very likely to me that by five years from now, people wearing cameras will be as ubiquitous as people wearing Walkmans were in the '80s.
Most of that revolution has already happened. Huge numbers of people (at least in the urban US) have cell phones that record video; anytime anything exciting or unusual happens in a public urban space in the US with more than a dozen people nearby, you can be pretty sure someone will record a video of it. Wearable video cameras just take that existing fact to the next level.
Mark Hurst at Creative Good talks about the experience of non-Glass-wearers when everything is being recorded and indexed for posterity. The privacy issues are real, and very much worth discussing.
But I think it's also important to think about this stuff in terms of when, not if. In five years, I expect there to be wearable cameras everywhere. Given that, what are we going to do with and about them? How will and should society react? Some spaces will indubitably try to ban them, but most public spaces can't and won't, so instead of thinking about how best to ban them, I would argue that we should be thinking about how best to adapt to them, as a society.
(To be clear: Hurst doesn't argue that we should ban them; I'm not disagreeing with Hurst.)
(Disclaimer: As always, I do not speak for my company.)