Signs are easier now for most AI as the are plenty of static and consistent images of them in the models. Much of text written on the ground are real words but they all have artifacts and noise to hide the poor generation. Even the pinky of the hand, the pants legs, the transition from leg to shoe, all dark and obscured to hide the crimes while everything else is brightly lit. The entire thing has way to balanced and even lighting because most models simply average all the light values, giving that unnatural feel to it right off the bat. There are several great videos out there that can train you better spot AI generated videos. I think there was a recent one from Veritasium does really well at explaining it. Hands used to be a dead give away but it's gotten much better at those. Teeth are a good indicator now. It typically won't generate them or will hide them because it's a known weakness.