Today’s invention provides a way for people who feel surrounded by security cameras to detect their blindspots and thus maintain some privacy (presumably such spots are by definition of no significance for actual security).
It is essentially a torch which projects a bright, conical beam and which can be attached to the outside of a security camera housing. The beam’s lightcone might be adjustable to be just wider than the normal angle subtended by a camera lens. By aligning it with the housing’s long axis, the beam can be made to shine wherever the camera is ‘looking’…thus leaving unsurveilled regions in comparative darkness.

The torch would move with any motion of the camera and it would also be possible to see where several cameras’ viewfields intersected.