So Austin had NO IDEA what ' Cinderella' looked like.
Even if he didn't know her name, and the mask was hiding her face, he could've recognized her voice and blonde hair.
He could've limited him search to only blonde girls instead of holding auditions for the entire school.
Plus, didn't her cell phone have a camera phone on it.
Yes, flip phones in 2004 DID have camera phones, they were just smaller, he could've looked through it and possibly find pictures of Sam.