Just a little clarification on my last post.
Technically, the "demo" CD was actually a "system evaluation" CD. It was used for judging systems in car audio competition. As system designer/installer, we never knew exactly what cuts the judges would select for system evaluation. So, we would make sure the customer was familiar with how all the tracks sounded on their system. A good way to motivate the customer to listen to all the music on the CD.