I would say based on my high school journalism class, not very! Reporters are trained to be observant. Eyewitnesses to accidents or crimes are pretty shoddy. Just today I saw a guy almost get run over right in front of me (we have a horrible new local pedestrian law that is actually causing more accidents) and I was distracted.

Just wanted to say - I was not the person driving! I was going to walk across also, but from the other direction as the person who almost got nailed. So the offending driver was right in front of me.