Right, but adding a big memory chip may be difficult in a video camera that must be as small as possible, except when using some expensive packaging method, with chip stacking.

Ensuring almost perfect shielding is cheaper and simpler. The camera should be completely enclosed in a metallic case, with only 2 small holes, for the camera lens and for the antenna output. Also its schematic should include adequate filtering components superposed to the integrated circuit packages, to minimize the length of the metal traces with variable potential, which radiate electromagnetic waves.

Improved shielding and filtering should reduce a lot the detection distance from the 20 meter range obtained with ordinary cameras, perhaps to a range under 1 meter.

If the camera is designed to not watch continuously, but to halt its activity for random intervals, it may have great chances to not be detected even by close sweeps with the camera detector.