Tesla Vision fails as owners complain of Model 3 cameras fogging up in cold weather
(www.notebookcheck.net)
Think of that Coyote and the roadrunner cartoon. If there's a graffiti that looks like a tunnel the coyote may run into the tunnel based on vision alone, but a secondary sensor will help telling that there's a wall.
Irl, If the vision failed to recognize that there's something on the road, at least a secondary sensor will protest that there's something on the road.