What would be great is if judiciaries only treated video as admissible if it was cryptographically watermarked in tandem with a globally distributed blockchain-

What would be great is if judiciaries only treated video as admissible if it was cryptographically watermarked in tandem with a globally distributed blockchain-style rolling checksum, to resist tampering (deepfakes or just plain old timecode manipulation). Combine that with a licensing scheme, as a condition of using the global checksum service, that guaranteed by law access to video by any party captured on said video — i.e. scenes & events in public areas would be required to be made available to members of the public, on request; or video of private areas would still have to be shared with any subjects that it captured, if it were to be introduced as evidence.