No, I meant that the screen could mess up the video stream shown so that it would look "fine" for the human eye but as a completely scrambled mess to a camera. You know how hard it was to film a CRT-monitor and AFAIK there have been some (abandoned) research on how to put something like that into LED specifically do defy the screen-capturing.
CRTs were never impossible to film - you just had to put in some effort to adjust shutter settings on the camera.
I can’t imagine there existing a technique for emitting photons perceptible to the human eye and yet it not being possible for a camera to capture them.
Got it, that makes sense. With monitors now in 60-120Hz being common, that might be doable.
The camera DSP might shut off if it detects a watermarked signal.