Could be some middle ground. That video doesn't really help his case to me. He knows the car is in the middle of the street, and not parked. The driver does start rolling while the passenger is clearly very close to the car. Even if you assume he didn't notice the car leaving, it seems to speak to the drivers intent. If the driver was intending to steal something, why risk pulling away when the owner of the bag is so close?
It's plausible to me that the driver didn't hear, or didn't pay full attention to the request to wait, and just pulled away...and that the bag was taken by a later passenger.
I would have been happy to get the money, and probably would have skipped the blog post.