While using parole from git, the Media menu always says "insert disc" regardless of whether or not I have a dvd in the drive. I don't have any CDs on my at the second but I assume the behaviour is the same. I haven't taken a look at the code yet but if I had to guess it's not even looking for the discs, given the lack of spinning up.
I've noticed this as well, and it seems like Parole does not mount discs. If you mount the disc elsewhere (such as Thunar), Parole always detects it and works as expected.
closed since it works if DVDs are mounted.
@sean feel free to open up a new feature request for yours, it just doesn't belong on this bug :)