I'm kind of disappointed that Steve Krug didn't think up something like this for _Rocket Surgery Made Easy_ (http://www.sensible.com/rocketsurgery/index.html); this would be a very convenient source of manpower for his model of "hallway usability testing," and would allow even larger numbers of even more easily set-up tests than the model he describes.

It's good to see how usability testing is becoming de-mythologized these days; all of us should keep in mind, for current and future program development, that you really don't need a very sophisticated apparatus.