Google Glass developer policies explicitly disallows facial recognition apps. The company also said that developers would not be allowed to disable the Google Glass display while using the devices camera. This comes in response to concerns that Glass wearers could surreptitiously take photos and videos of their surroundings without those nearby being able to see that they were doing so by noticing the lit display in front of their faces. Google pulled in existing Android policies for hate speech, gambling and explicit material to the Glass terms.”]
Source: https://allthingsd.com/20130531/google-disallows-facial-recognition-in-glass-apps/