It seems that most of the news stories I see about Google Glass these days are about privacy and ethics concerns. The common question is, effectively: "Is it acceptable for a someone to carry a concealable video camera around wherever they go?"
I think that these fears are somewhat misplaced. If anyone living in an urban environment thinks that they're not frequently being video-recorded, they're fooling themselves. Also, I honestly don't see how this is much different than the video cameras embedded in most smartphones these days. Should we ban smartphones from public places as well to prevent this kind of casual surveillance?
(As an aside, I think that there are larger issues than just privacy at stake. By allowing people to video-record their everyday lives, are we working toward a world where one's own ability to remember facts becomes obsolete? After all, if you can look up facts online instantly through vehicles such as Wikipedia, and if you gain the ability to digitize and store your own experiences for future reference, is there any need to remember things using your own brain? Will we, as a race, lose the ability to remember things for ourselves, offloading this responsibility to a ubiquitous global cloud of data storage?)
But the most important fact that these discussions seem to overlook is the fact that Google Glass is only one early implementation of a personal, wearable, video input-output device. Even if Google Glass is a commercial flop, or even if some enormous public outcry caused Google to shelve the project, someone else will produce another version of this technology sooner or later -- probably sooner. No matter how uncomfortable some people feel about the Google Glass concept, this idea isn't going to go away. In ten or twenty years, wearable computers will be everywhere, and we'll either have developed some sort of etiquette system around them, or we'll just all pretend they don't exist.
We humans have been working on ways to mechanize ourselves for a long, long time, and we're not going to stop because a bar somewhere in Seattle doesn't like the idea.