The evil music industry is making life in ZUNE land difficult.  According to this article, both Universal and SONY are adding select artists into their “No Zune Sharing” lists…

There is a lot of testing going on at Zunerama and ZuneThoughts about songs that can or cannot be shared when purchased or acquired through the ZunePass. Both sites are coming with numbers of around 40% of songs that “can’t” be shared from Zune to Zune. This is an important number considering that on of the key highlight of the Zune marketing is based on sharing and Wifi. Indeed, the Wireless device inside the Zune can only be used for sharing. 

Source: ClicZune