Prior to the passage of the ban on open carrying unloaded handguns in non-prohibited public places, a judge ruled in a lawsuit challenging CA's "may issue" CCW system.
The judge ruled that CA had to allow for a method for citizens to carry a handgun for protection and that the current "may issue" CCW system was legal because a person could UOC as an alternative.
With the UOC ban, the court ruling has been appealed because the other option for not being able to get a permit has been taken away by the state.
Therefore, the UOC ban helps the "shall issue" CCW fight for CA.
On another note, there has been a lawsuit filed to challenge CA's ban on open carrying loaded firearms in public places (Mulford Act of 1967).
Also, a new bill was introduced to ban the unloaded open carry of long guns (rifles/shotguns). This bill was introduced due to the UOC people open carrying unloaded rifles the day the UOC ban went into effect.