Amber is a close friend of David Snyder's. She agreed to help us out, when we were desperate for student extras our first weekend of filming, just days before moving down to Florida. She even stayed late to help us film the scene in front of the locker room door, although that scene eventually had to be redone due to sound problems, with Dawn Reilly filling in as the student that walks by David and Jonathan in the hallway.
The original scene, with Amber in it, can be viewed under Deleted Scenes on the DVD, along with another scene in which Amber participated - the first take of the "Gym Scene".
Since Amber didn't like the idea of appearing in the credits as something as bland as Student #1 or Student #2, we settled on Student #1A.