According to this article in the LA Times, the UC board of regents have determined they have the authority to block UCLA from joining the B1G. "All options are on the table" says  Regent John Perez. This includes prohibiting UCLA's move, but also may include the possibility of UCLA striking a deal and using part of their B1G windfall to subsidize Cal in the sure to be reduced media deal from the PAC 12. 

A question I have is if you remember the reports when all of this started a couple of months ago, USC and UCLA didn't know they were both independently applying to the B1G  which leads me to believe both were willing to move to the B1G without the other. If the UC BoR nixes the UCLA move, will USC care?