That statement is just decoration. Maybe their end paragraph wasn't long enough for aesthetic purposes.
They mean to say that each person can only use this once, but there's literally no way to enforce this. Even assuming they keep all your information on electronic file (and no one is less than completely honest about their contact information), you can still ask your mom or brother or best friend. Realistically, 3 days isn't enough time for you to use it that many times anyway.