Zune Pass software makes your music vanish?

From time to time, every music service software will happily see to it that some of your music vanishes because of digital rights issues and other legal matters.  As of late, Microsoft's Zune Pass subscription service seems to make more and more music from collections evaporate into thin air with an alarmingly higher rate.

Users have registered similar complaints on the Zune forums, disappearing acts ranging from  including all the music from some artists (Arcade Fire, Vampire Weekend, and Spoon, and others), while others have seen only some albums, or some songs disappear.

The software giant's customer service reportedly responded  to users that their music has gone away because record labels have pulled them, but reports from users indicate that there's not much logic to that answer.  Any Zune Pass users have music that has escaped their libraries?  iTunes isn't the greatest, but at least it doesn't go near your music with an axe to grind.