Google Alerts are like the best little gnomes, they bring you shiny things, hoping that you like them. Things like "Multiuser interaction with handheld projectors". And the Youtube videos they spawned from.
I commented, I like my gnomes that much:
Interesting. That’s perhaps the very first example I’ve seen of real world tasks being performed in an Augmented Reality environment. I share your hesitance over the actual usefulness of projector technology, but I can easily imagine this kind of research being very useful when applied to a Heads Up Display environment - no issues of privacy there. In fact it could be worse - if two people are wearing HUDs and ‘think’ they’re seeing the same view, one of them could have been hacked, etc and could be manipulated into authorising something they wouldn’t otherwise.
I don't think anyone is thinking much about AR and security yet, unless it's the Defcon folks hacking Bluetooth.