From 1988 to 1997, I worked predominately as an extra and stand-in (becoming a member of SAG in late 1991 after being given dialogue on a scene from CHAPLIN that was cut from the final version).
Between 1998 and 1990, I did occasional volunteer production assistant work on American Film Institute first-and-second-year video and film projects. One of those projects was a few days on the shoot of a short titled MARILYN HOTCHKISS' BALLROOM DANCING AND CHARM SCHOOL, directed by Randall Miller.
Yes, the same Randall Miller who recently began directing a Gregg Allman biopic titled MIDNIGHT RIDER, where Sarah Jones, a camera assistant, was killed in a tragic accident involving a train and a bed (being used in a dream sequence) on the tracks.
[Recalling the AFI shoot in 1989, I had no real contact with Randall Miller; instead I worked with one of the producers and other crew members.]
This article by Sheelah Kolhatkar for BLOOMBERG BUSINESSWEEK summarizes the MIDNIGHT RIDER tragedy and its aftermath so far: http://www.businessweek.com/articles/2014-02-27/will-death-on-midnight-rider-set-be-a-reckoning-for-filmmakers
And here's a key paragraph:
Making movies often involves complex stunts and the use of potentially dangerous equipment operated by people who are typically sleep-deprived from 16-hour work days. Film productions are run like the military. If a director arrives and announces that he or she wants to do something that sounds crazy, like dangle the camera from a high rooftop during a windstorm, people are unlikely to object. One film worker and an acquaintance of Jones called for a national safety campaign to be named in her honor.
Now for a true happened-to-me anecdote:
I was a stand-in on a film (shot in Los Angeles) in 1995 (a family comedy which will go unnamed here). The first assistant director (who will also go unnamed) made it clear to the stand-ins that they would occasionally be required to do production assistant work--making it clear that to object meant being fired. This was due to the production company's eagerness to cut below-the-line costs when possible. (Towards the end of the shoot, it even extended to not using all the stand-ins on certain days, even when all the principal cast members were working.)
One day, the first AD had me climb on the top of the set to (as I recall correctly) hold a certain object through a hole (so actors would have an "eyeline" to focus upon). The scene involved family members in the basement suspecting they were being spied on.
Fortunately for me, the set was well built, I did what was asked of me and I didn't crash to the floor and suffer injuries.
I'll close with a link to the story of another young woman who worked as an extra and was persuaded to drive a car during a scene where stunts were occurring. This film I'll mention by name: TRANSFORMERS 3.
[UPDATE 7/3/14: Randall Miller, his wife and co-producer Jody Slevin and Jay Sedrish, unit production manager and executive producer, were charged with involuntary manslaughter in Sarah Jones' death. Here's a link to an article from the London GUARDIAN: