Your walls have cameras in them. They put rails on the inside that disintegrate, when they come into contact with outside air (or perhaps light). The cameras are fastened to these rails and fixed with drills, so that they can create small holes when needed and fix them when they are no longer needed. The cameras are then able to follow you around your house and wirelessly report back to their creators with the video data.
This is why it's illegal everywhere in the world to own a radiowave blocker; they block the camera signals.

Build your own house.