A lot of spy movies or police procedural movies show someone coming with a magic detector for hidden spying cameras or microphones that is used to sweep a room and remove all offending devices.

The device presented in the parent article would be undetectable by any classic detectors.

However, if such a method would ever become widely used in reality, it would not be difficult to make detectors for it. So it could have a window of opportunity, between the first development of spying devices based on it and the development of countermeasures.