These seems to be much more robotics / autonomous vehicle focused? I don't quite see the mass surveillance angle you get from this you don't already get from cheap ubiquitous cameras, basic computer vision and networking (aka flock) .

I think you've made the erroneous assumption that the researchers care. I work in 3D reconstruction and I've not really seen too many people care about the actual use case, and indeed have had some friends join defence.

I'm not sure what you mean. The input video feed already constitutes "surveillance". You'd need cameras everywhere and if you have a camera, you can also just use regular models like China already does.

N00b question from me, perhaps, but how easy is it to mount and run Lidar on aerial drones?

Video cameras are much cheaper and easier to use than LIDAR, like anyone can just pull out their phone, take a video and send it to this algorithm to get a reasonable point cloud of the environment. Sure, if you want an exact model of an environment and you have the time and money, LIDAR would give better results, but this is about doing more with less