When Google first announced that they were working on Google Glass, opinions varied widely, especially because a lot of people were worried about privacy issues, and this has led Google to make some changes: they have taken out the facial recognition function.
As fascinating and futuristic as the glass might be, the concerns are real and Google realises that. According to the official announcement on Google+, they “won’t add facial recognition features to our products without having strong privacy protections in place.” Since these privacy protections are not good enough yet, they have decided to leave out the facial recognition feature all together.
Similarly, Google has already made sure that it will not be possible to use the camera with the screen off, to avoid people being able to secretly make pictures. This shows that Google is listening very closely to what people have to say, and they seem to take the testing phase very seriously.
"We’ve learned a lot from you in just a few weeks," they wrote on Google+, "and we’ll continue to learn more as we update the software and evolve our policies in the weeks and months ahead."