Sounds like a great start for a dystopian sci-fi novel. Just imagine the effect it will have on our social habits when we start avoiding people that our Google Lens HUD marks as non-trusted. It doesn't even need to happen in a malicious way. All you need is the contrast between the people marked "green" and those you haven't added to your trust list.

The short movie "Sight" is a great demonstration of our potential near future of augemented reality technology and the effect it might have on our social lives: http://vimeo.com/46304267

Like a Motorola Skip, or any number of other NFC tags that will do this?

http://www.motorola.com/us/accessory-family-page-1/Motorola-...

To clarify, I meant this as a matter of ubiquity...

There are options for this functionality out there, of course, but they've not been adopted much by users.