Just like https certificate authorities, the only way to fight all the AI slop will be "trusted" camera firmware that signs every image with a full chain of trust that the output was a real physical video taken will a real device at a real location.
In most places (for example outdoors), it would be extremely obvious that you are filming a monitor.
If you had some sort of closed box setup to minimize external light sources and produce a realistic image, then it would be pretty impractical to carry that around. And perhaps illegal (in OP's theoretical world)