He didn't do anything. He trespassed.

That's why you send the video to the police. You don't gather up a lynch mob, or posse, to hunt the man down.

How did the guy shooting the video, just happen to be there? He was in on it.

The guy was running because he saw a bunch of Deliverance or Easy Rider rednecks after him.

And he was probably smart enough to know, those rednecks will probably kill him for spittin' on the sidewalk.