So though Wifi probably won't hurt you, it lets them spy on you!

Quote WiFi signals are everywhere these days. Unmanned aerial vehicles are expected to become a part of our near-future society. In this paper, we are interested in the possibilities created at this intersection of robotics and communication. More specifically, we propose a new methodology that enables the first demonstration of high-resolution 3D through-wall imaging of completely unknown areas, using only WiFi signals and unmanned aerial vehicles.
this was done at my old stomping grounds; it's fun to see the buildings in the background. And my favorite part of the video is when they describe the techniques used. Who would have guessed that it's an NP hard problem but you can efficiently solve it using Sum-Product Loopy Belief Propagation??? and who says science isn't funny.

https://www.youtube.com/watch?v=THu3ZvAHI9A

https://www.ece.ucsb.edu/~ymostofi/3DThroughWallImaging.html