(a) Curfew. It is unlawful for any minor under the age of 18, who is subject to compulsory education or to compulsory continuation education, alone or in concert with others, to be present in or upon the public streets, highways, roads, alleys, parks, playgrounds, or other public grounds, public places, public buildings, places or amusement and eating places, vacant lots or any place open to the public during the hours of the day when the school, which the minor would normally attend, is in session, on days when that school is in session.
(b) Exceptions. The provisions of this section shall not apply when:
(1) The minor is accompanied by his or her parent, guardian, other adult person authorized by the parent or guardian having the care or custody of the minor; or
(2) The minor is on an emergency errand directed by his or her parent, guardian or other adult person having the care or custody of the minor; or
(3) The minor is going directly to or coming directly from their place of gainful employment; or
(4) The minor is going directly to or coming directly from a medical appointment; or
(5) The minor has permission to leave campus for lunch and has in his or her possession a valid, school-issued off-campus permit; or
(6) The presence of the minor in one or more of the places identified in Subsection (a) is connected with or required with respect to a business, trade, profession or occupation in which the minor is lawfully engaged; or
(7) The minor is involved in an emergency such as a fire, natural disaster, automobile accident, a situation requiring immediate action to prevent serious bodily injury or loss of life, or any unforeseen combination of circumstances or the resulting state, which calls for immediate action; or
(8) The minor is in a motor vehicle involved in interstate travel; or
(9) The minor is authorized to be absent from his or her school pursuant to the provisions of California Education Code Section 48205, or any other applicable state or federal law.
(c) Enforcement. Before taking any action to enforce the provisions of this section, police officers shall ask the apparent offender's age and reason for being in the public place during curfew hours. The officer shall not issue a citation or make an arrest under this section unless the officer reasonably believes that an offense has occurred and that, based on any responses and other circumstances, no exceptions to this section apply.
If her school day on campus did not begin until after 2nd period, then she should be able to get the matter dismissed quickly with the proper documentation from the ROP teacher. Assuming, of course, that the student was also granted permission to remain off campus during that time. if required to be ON campus, then the offense still applies.