Police aren’t celebrities, so they’re not always used to being photographed in public. So even if you’re recording at a safe distance, they might approach and ask what you are doing. Avoid saying things like “I’m recording you to make sure you’re doing your job right” or “I don’t trust you.”
Google developers update;
"...A couple weeks ago, we held two hackathons for a small group of lucky developers from among those who signed up for the Glass Explorer Program at Google I/O 2012. We called these events the Glass Foundry. In San Francisco and New York, the selected Glass Explorers were able to spend two days with Glass and the API we’ve developed. They formed teams and built over 80 new ways to use Glass. Everyone who demoed received a special edition glass bar identifying them as a “Pioneer” of this next generation of computing. Eight hard-working teams won the grand prize: Google will pick up the cost of their Glass Explorer Edition."
“I’m not going to speculate [about Glass] because time will tell with regards what is the right execution with regards to this idea of “heads-up”, so I think we’ve a lot of work to do, frankly, so I’m not going to speculate about that” Pannenbecker said. “But I think, as I said, this is for me an area that we want to engage in, I mean, this topic of heads-up not this particular solution for example. As I said, there’s a whole bandwidth of opportunities, and I think we as a company need to look very deeply into these opportunities, and then commit.”
"...Many of my systems, like Google Glass, modify the view of just one eye. I find this works well. But I arrange the optics so that the camera takes in exactly the same perspective as that eye does. I also position the display so that the wearer sees it directly ahead and doesn’t have to look up (as is necessary with Google Glass), down, or sideways to view it."