As intrusive as the Google Glass has proven to be, it will only be worse when observation recording tech is more difficult to detect.
I disagree. The exact opposite: when people stop noticing, they will stop caring. It won't be perceived as intrusive anymore, and people will be less annoyed by it.
It's the conspicuousness of the camera in Google Glass, the constant reminder that you might be recorded, that makes most people feel creeped out. For the previous decade leading up to that product, nobody cared about small+cheap camera tech itself. And people walk/drive by fixed-position cameras all the time, and don't give a fuck there either. Peoples's behavior shows that "intrusiveness" happens when a cameras looks like a camera, and I suspect it also has something to do with being face-level, literally "in your face" and you're making eye contact with it, unlike the case with less conspicuous cameras. It was never about privacy; it's some aspect of self-consciousness kind of related to privacy, but a different thing.
You might say "maybe you, but I sure care. Hell yes it's about privacy." Of course you say that. I'm talking about how people behave and the emotions they display. Not their innermost secret thoughts that they are always terrified to express in voting booths or policy decisions, yet are happy to speak of on the Internet.
You know, the Internet, where they don't have a camera in their face making them all self-conscious! The Internet, where instead of a terrifying 1x1 pixel image that makes you think "WTF is that? That's weird! Are you watching me?" you now instead see a bunch of "like buttons" which are obviously for liking things, not getting your browser to send a request to an unrelated tracking server.
In addition, there's a certain inevitability about it all. The cameras have been there a long time, there are more today, and there will be even more tomorrow. You can't do anything about it, except stay at home. So you'll either accept or you'll go insane and get selected out. You'll handle it. (Contrast that to Google Glass, the one small camera out of the hundreds out there, that you actually recognize and is also rare enough that there's little social cost to shunning. With GG you can refuse to accept and also stay within social norms, so GG is different.)