I'm guessing the Riskiest Assumption with Glass is that people would be willing to wear a cumbersome piece of technology, with a "red light" to say when it was

I'm guessing the Riskiest Assumption with Glass is that people would be willing to wear a cumbersome piece of technology, with a "red light" to say when it was recording on their face in exchange for a HUD. They field tested that idea with a small group of early adopters and found that it wouldn't fly.