That's not how it works: that either there is an assumption or there is no assumption. The assumption may weaken, but what will happen is that if someone sends

That's not how it works: that either there is an assumption or there is no assumption. The assumption may weaken, but what will happen is that if someone sends a fake video to many people, you're guaranteed that a substantial fraction will believe it's real. I mean, a big portion of the population believe in outlandish conspiracy theories. You're way overestimating people's skepticism.