Trucks are loud, and if they don't hear scraping, they're not going to hear shouting.

To be clear, I'm not trying to defend bad autonomous vehicles here - just pointing out that the dangers exist with any large vehicle. This is something that happens with trucks, so people should be aware.

*Since you don't seem to believe it's possible, here's a news report of an incident from 2017: https://www.youtube.com/watch?v=Q22sQndSjEA