I believe that was the primary thrust of the argument from the lawyer in the California Supreme Court case, referencing more specifically the equal protection clause in the state constitution. Sadly the judges did not seem very impressed and the lawyer did not fair well when prodded further on the issue by the judges. Perhaps he was flaberghasted that they did not see the immediate truth behind his argument.As much as anything I think it is a 14th Amendment Equal Protection issue.
I hadn't heard anything lately. A quick news check says the decision from the California Supreme Court is due by June 1st.