Update: Chris Boyce, Director of Programming for CBC Radio has responded to the public comments on the issue by clarifying that the reason for blocking the use of CC licenced music from podcasts is not the result of contractual restrictions, as other CBC employees previously reported. Instead, Boyce says that many CC licenced works carry restrictions on commercial use and that some podcasts have a commercial component. That is a much more sensible explanation, yet it does not explain why all CC licenced music is blocked from podcasts. Some CC licenced music can be used for commercial purposes (the Spark CC music playlist contains such a track). A better approach – one that respects the choices of both artist and producer – would be to require that programs only use music with the appropriate rights, which could include some CC licenced music.
Update II: Creative Commons responds, noting the availability of CC licenced music for commercial uses.