I wish I had mod points. This is the fundamental problem with Google Glass.
The fundamental problem is people assuming that if I'm wearing Glass I must be recording them. Eventually this fear will go away. Glass is the worst possible device to record/picture anything without being noticed. There's no zoom, you can't really aim (you must be looking at the target, and you will just get a picture of the general area you are looking at).... really, sucks for that.
Glass is a nice toy, but not because it makes spying easier, which as I said, it doesn't.
In general, if you see someone with Glass, you can bet they're actually playing with it and totally ignoring you -or anyone else for that matter-, at least if they just got it. If they've had it for a few months then nothing is happening, except that they might get the occasional notification.
I think we will get used to it, same as we do with cell phones, and an acceptable etiquette will develop.