Nobody saw a gun in a video. Nobody even saw something that looked like a gun. A chip bag, at most, is going to produce a bulge. No reasonable human is going to look at a kid with a random bulge in their pocket and assume gun. Otherwise we might as well start sending our kids to school naked; this is the kind of paranoia that brought us the McMartin Preschool nonsense.
The presence or absence of human review is irrelevant. A system with stupid humans are just as bad as a system with stupid machines. They are complementary, really.
Nobody saw a gun. We know this because there was no gun.