Boy, what a tough crowd. What I get lost on is the intent of "shadowing". I didn't think that was "training". I sent my son to his private school, along with others, to "shadow" to determine if that was the right one for him. He didn't have to sit and do the school work, nor was he attributed time for his education. He was considered absent from his normal school.
Hopefully an attorney can chime in, but I believe that unless she filled out tax forms, or has a piece of paper that acknowledges her as an employee, she's not. A day of shadowing is just that. Stand in the corner and watch, taking in information to make that final decision. She shouldn't have been required to lift a finger, and if she did, it was volunteer. However, it wouldn't be worth the $80 argument, just an $80 lesson learned to make it clear for the next one. Just my two pennies....