You are not understanding the trust issue.

By default, patents trust doctors with their bodies so they don’t expect the doctor to do shady stuff like record them with a hidden camera. However, the moment they see something that suggest they might be recording,then the hidden voice awakens and questions everything the doctor has done in a new, not so trustworthy way.

It’s not that patients think that doctors who wear those glasses won’t have a hidden camera too, it’s that doctors who have those glasses might also have a hidden camera, it’s the fact that they have those glasses that opens the patient to other shady possibilities.

As others have said, trust is broken.