Source control would certainly help establish a history of incrementally performing school work by someone when viewed by a highly technical examiner and when periodically stored someplace where a trusted 3rd party can confirm it wasn't all generated the night after a supposed false positive.

However, hundreds of hours of video is compelling to non-technical audiences and even more importantly is a preponderance of evidence that's going to be particularly damning if played in front of a PTA meeting.

With a git history it's going to come down to who can spin the better story. The video is the story and everyone recognizes it, so I expect fewer people would bother even challenging its authenticity.