We already have evidence he knew, since it's by a very wide margin the most reasonable explanation for the presence of those documents at his private residence a year and a half later, even after many months of the government trying to talk him into returning his stolen docs. But, if we had that video, etc., all it would mean from a Trumpist perspective is the need to fall back to whatever other defense he offered. Maybe the video was a deep fake. Maybe the docs had been declassified through an order that the Biden administration has since hidden. The cult leader can never do wrong, so all of reality must bend to the extent needed to support his righteousness.When you have a video of Trump telling his movers to take certain classified documents to Mar-a Lago, then showing them packing them in trunks, then the movers loading those trunks into their trucks, then (all uninterrrupted), the trucks traveling from DC to Palm Beach, then putting them inside a room in Mar-a-Lago, and then Trump looking at the documents inside Mar-a Lago........THEN you may have evidence that Trump knew the documents had moved from the White House to Mar-a Lago.