She can use the pass to get up to 3 people in 6 times during her program. It works by the number of times so whether she brings in 1 person or 3 people it still counts as 1 time. There is no role over. It works just like a Park Hopper, in fact when you go to the CM turnstile she shows her ID and the Maingate is scanned. They give paper tickets to her guests, to use for park hopping/fast pass etc. She uses her ID for these items.
She does need to enter the park with you. She cannot give you the pass to enter the park. (My roommate mistakenly did this and her mother made a scene that nearly got her termed). She is essentially responsible for you, so if she were to leave you at the park and you got in trouble for something she could be terminated.
