If you`ve ever been on a set you know that extras are like second class citizens onset. As an extra you don`t do anything on your own and you definitely don`t talk on camera since you don`t have lines and don`t get any lines as an extra. Its actually a good way to get kicked off a set. Productions pay a heavy fine to give an extra lines, which almost never happens since they can simply get a SAG actor to do it without paying any fines. In this scene from Being John Malkovich with directors commentary we see an extra who sneaked beer onto the set. This guy is supposed to be barely even be seen, as a passenger in a truck that drives by.
