Comment 29 for bug 561585

"jocko, if you are sure that http://launchpadlibrarian.net/43952779/cdrom_id_151-5.trace is really from -5 (and not from -8), this would prove that the question whether it works or not does not really depend on the particular udev version, but rather that installing a package triggers the change.

Can you try if the cdrom_id output changes if you do

  sudo apt-get install --reinstall udev

? The critical piece what to watch out for is if the cdrom_id /dev/sr0 output contains ID_CDROM_MEDIA_STATE=blank; if it does, things should work."

I think those strace outputs I provided were without any disk in the drive (sorry about that), so they may not have provided the right information...
But I've upgraded from -8 to -10 and it seems to work fine now. IF (and only if) the problem reappears I will get back here with the proper strace output, but I'm pretty sure it's fixed.

Thanks Martin!