Cal. Penal Code § 627.3

In order to register, an outsider shall upon request furnish the principal or designee with the following:

(1) His or her name, address, and occupation.
(2) His or her age, if less than 21.
(3) His or her purpose in entering school grounds.
(4) Proof of identity.
(5) Other information consistent with the purposes of this chapter and with other provisions of law.
No person who furnishes the information and the proof of identity required by this section shall be refused registration except as provided by Section 627.4.