From first hand experience EXIF data will not serve the purpose either because it can be removed or altered. In court my team spent a day and a half proving we had the right to take the photo (and video) in the first place.
Despite a contract the corporation argued because their logo/TM appeared in the photo, that photo was free for their use. They were willing to pay for others. We settled out of court. Hence my remarks about ownership being an expensive business and diplomatic solutions far wiser.