California Code, Insurance Code - INS § 12693.83

(a) It shall constitute an unfair labor practice contrary to public policy and enforceable under Section 95 of the Labor Code for any employer to change the employee-employer share-of-cost ratio based upon the employee's wage base or job classification or to make any modification of coverage for employees and employee's dependents in order that the employees or employee's dependents enroll in the program established pursuant to this part.