I was thinking about it cus of this video (https://www.youtube.com/watch?v=-7ngS1fgoYk) which to spoil things is just a stealth advertisement for a solo TTRPG (which I did decide to check out so, mission sucess?)
One deliberate tell I've seen in a couple of unfiction videos is that by the end of it, they'll have end credits that's deliberately styled after movie credits, which is fairly unusual for for video essays. They might have credits, but usually in the form of end cards with a different visual language.
I find this kinda fascinating cus they dont outright say "this is fake", but by styling it after something known to be fiction ,they can plant that seed without outright stating it.