Suckafree answered pretty well, but I'll touch on yours which click on, like baby cams. They aim to preserve power and usage life by reducing the time it is on until it is needed. Almost all security cameras broadcast the IR 24/7 to highlight dark areas and features of the individuals, but it also creates glare and reflection. A lot of savvy criminals will wear strips of reflective tape or something like that to blind the camera.
Suckafree answered pretty well, but I'll touch on yours which click on, like baby cams. They aim to preserve power and usage life by reducing the time it is on until it is needed. Almost all security cameras broadcast the IR 24/7 to highlight dark areas and features of the individuals, but it also creates glare and reflection. A lot of savvy criminals will wear strips of reflective tape or something like that to blind the camera.