I think this is a bad indicator of interest. Demos in public spaces are tough, especially at a store. Setting is important - many people understandably don't want to flail around in a public space when they can't perceive what is going on around them. I have given public demos of both the HoloLens and Oculus Rift and I can say that I had a bunch of people say that they were too embarrassed to put on the Oculus when there were people around. With the HoloLens I could explain that they could still see the "real world" and they would be a lot more likely to try it even if they were shy.