When i was in the police I’d often collect CCTV from store owners etc.

I’d usually supervise the download to make sure I only got what I needed. In my statement I’d reference that I’d supervised the download and that the footage hadn’t been tampered with.

It wasnt a big deal.

Adding on that as a compulsory requirement, or making it so CCTV systems add hidden info into the meta data wouldn’t be difficult.