the point of the music is that it leads the way into relaxation , it is the oldest and most important sense we have see
www.birthpsychology.com for more on this and the importance for babies that they hear music. but for you it is a support and comfort , it is much harder to access feeling deeply relaxed without music and thats why it is such an important part of the course.
it is also important that your concious mind screens out distractions , and listening to music is one way of helping your conscious mind to do that. So when you are in a relaxed state , you stay there and are not tempted to jump in and out of that relaxed state, since the concious mind is forever busy , and asking us to be distracted it takes training and discipline to ignore that unhelpful thought and music is helping us again to put our foot down to that thought , so we stay relaxed.
if someone is resistant to the music , then they need to ask themselves why is their conscious mind so contrary and can those concerns be allayed, so the resistance fades. hope this answers your query ,
Eleanor