I wrote an open source face recognition demo here for Google Glass if anyone is interested: http://www.youtube.com/watch?v=E1aeMJY1AO0 https://github.com/lnanek/MedRefGlass

It doesn't use lambda labs since they weren't out yet, but it is just as easy to use other APIs anyway.

After the current NSA scandal, is there any chance for wide adoption of a wearable mass spying device ?

Yes. Just ensure that the glasses always show an LED when recording, one that can't be controlled by software drivers.

And what if if stand a few meters from a google glass user and don't see the led?

You can easily pick out the recording LED on camera equipment from 30m so that's not really an issue. The bigger problem is simply not noticing once glass becomes even slightly popular.

Or what if said glass user has heard of electrical tape?

Or even a bit of paint, done nicely.

You could easily make it completely opensource and standalone by replacing the calls to web-based api's like lambda or betaface, with the standalone face recognition engine from openbiometrics.org https://github.com/biometrics/openbr

If they don't like it its only because they want to be the only ones doing it. Seriously facial recognition is the one big technology useful on the glass and Google knows that and probably developed a lot for the glass itself.

They've said on twitter that glass is deliberately left open / unlocked.

Heh, I met this guy last week at a party. Small world when you're in the Bay Area I suppose.