It's also strange in that I don't think I'd get very much out of simply watching anyone work, unless they were also giving live commentary or something.
There was an article posted on HN a while back that claimed that the best way for beginners to learn a new skill is to watch an expert just work, without any commentary or explanation. I tried finding a link, but couldn't come up with working search terms on DDG, Goog, or HN.
This was an interesting article about the trend towards robotic surgery and the new methods to gain experience in such an environment.
Really seems like I should be better at golf, then. :tear
Casey Muratori's and Jonathan Blow's streams are pretty great in this regard. Both do low-level gamedev.
That's where pair programming can shine: when I see a junior who need help, I'll ask if they don't mind me coming around and helping. Just asking the right questions and guiding them to find a solution to their problem usually do the trick. And it helps me see the pain points of our code, documentation and specs.