if, as you say, it is some kind of prerequisite to getting on the course

There are not, as far as I am aware, any hard-and-fast 'prerequisites' for course entry (other than an ability to pay the fees). Prospective students are assesed individually on their merits. Clearly they wil be asked "Do you like playing traditional music?". If they do not, what exactly would be the point of applying for the course?