Now I may be wrong about this and will happily stand corrected if I am, but, as far as I can tell, none of the artists performing at the benefit have ever released an album or a major piece of work under a Creative Commons license — even the restrictive and non-free licenses.
The free culture movement needs some things more than money. For example, it needs high quality creative works under permissive licenses. We’d be better off with the good press associated with one hit single under a CC BY-SA license than all of the proceeds of a benefit like Friday’s. It might also be nice to highlight the great work being done by artists who are risking more secure economic models in favor of releasing their works under free licenses.
Or perhaps this reminds us of another important conversation: Why are many popular musicians who are willing to support CC unwilling or unable to use the licenses? More importantly, how are we going to change this?