The photography of an individual can constitute harassment even in a public place - there is no implied consent involved. Even if it were, as you implied, perfectly legal in all cases then this in no way makes the act ethical. This is especially true when concerning a new technology which makes it trivially easy to perform. I'd expect if Glass, or some descendant of it, becomes more ubiquitous, then social guideline and laws would eventually prohibit it's use in certain situations. Would you, for example, be happy with someone recording you in a public restroom?

You're also repeatedly missing the argument I've already made twice in this thread with your second paragraph,