There has to be a receiver network to monitor the patients, or a transmitter to
control the patients. The network would be much too intrusive to keep secret, and much too expensive to build or maintain. The transmitter would be broadcasting an unencrypted signal that any interested party would find and read — ruining the secret.
There must be a network of receivers. But that’s a lot of receivers, especially
if they’re terahertz or infrared receivers; even visible light requires line-of-sight to be useful, and all the other, stray sources of visible light have to be ignored. So God only knows what sort of imaginary detector the conspiracy theorists think is being used, there have to be a lot of them. Somebody has to make those receivers, install and maintain them. That’s a small army of employees, all of whom must be kept ignorant of their secret purpose, or must be willing participants in the conspiracy. That’s hard to swallow.
But suppose the installing army is actively participating in the secret? How do
you recruit such an army of installers without blowing the secret? “You’re going to be installing snooping devices all over town, but don’t tell anybody. Do you want the job?”