California Code, Penal Code - PEN § 384

(a) Any person who shall wilfully refuse to immediately relinquish a party line when informed that such line is needed for an emergency call, and in fact such line is needed for an emergency call, to a fire department or police department or for medical aid or ambulance service, or any person who shall secure the use of a party line by falsely stating that such line is needed for an emergency call, shall be guilty of a misdemeanor.

(b) “Party line” as used in this section means a subscribers' line telephone circuit, consisting of two or more main telephone stations connected therewith, each station with a distinctive ring or telephone number. “Emergency” as used in this section means a situation in which property or human life is in jeopardy and the prompt summoning of aid is essential.

(c) Every telephone directory hereafter published and distributed to the members of the general public in this State or in any portion thereof which lists the calling numbers of telephones of any telephone exchange located in this State shall contain a notice which explains the offense provided for in this section, such notice to be printed in type which is not smaller than any other type on the same page and to be preceded by the word “warning” printed in type at least as large as the largest type on the same page;  provided, that the provisions of this subdivision shall not apply to those directories distributed solely for business advertising purposes, commonly known as classified directories, nor to any telephone directory heretofore distributed to the general public. Any person, firm or corporation providing telephone service which distributes or causes to be distributed in this State copies of a telephone directory which is subject to the provisions of this section and which do not contain the notice herein provided for shall be guilty of a misdemeanor.