I had a similar experience as GearHead last summer when I was a very new shooter.

Karl yelled at me for having the barrel of my 10/22 more than 45 degrees off perpindicular to the firing line, and I'm glad he did because I wasn't paying attention (obviously not a good thing).

I can't think of anything other than that specifically, but overall everyone is pretty safety concious and the people not shooting tend to look out for the ones that are.

+1 on cameras making perspective all wonky for who's ahead/behind an imaginary line in space when you have little reference for how tall people are or how long their firearms are. That's not to say that people don't make mistakes, but every shoot I've been to has been really good about maintaining a proper firing line.