A more accessible thing that protects against fake videos, at least in the short term, is multiple cameras and a complicated background.

Maybe eventually we get a model that can take a video and "rotate" it, or generate a 3D scene that can be recorded at multiple angles. But maybe eventually we may get a model that can generate anything. For now, 4o can't maintain obvious consistency with so many details, and I imagine it's orders of magnitude harder to replicate spatial/lighting differences accurately enough to pass expert inspection.

If you want solid evidence that a video is real, ask for another angle. Meanwhile, anything that needs to be covered with a camera (security or witness) should have at least two.