The short answer is “no”. California Education Code, Section 45125.2 allows 3 methods to control construction contractors on school grounds who may be left alone while on campus. Here it is:
45125.2 is the section on construction contractors.
45125.2. (a) A school district contracting with an entity for the construction, reconstruction, rehabilitation, or repair of a school facility where the employees of the entity will have contact, other than limited contact, with pupils shall ensure the safety of the pupils by one or more of the following methods: (1) The installation of a physical barrier at the worksite to limit contact with pupils. (2) Continual supervision and monitoring of all employees of the entity by an employee of the entity whom the Department of Justice has ascertained has not been convicted of a violent or serious felony. For purposes of this paragraph, an employee of the entity may submit his or her fingerprints to the Department of Justice pursuant to subdivision (a) of Section 45125.1 and the department shall comply with subdivision (d) of Section 45125.1. (3) Surveillance of employees of the entity by school personnel. (b) An entity that contracts with a school district for the construction, reconstruction, rehabilitation, or repair of a school facility is not required to comply with the requirements of Section 45125.1 if one or more of the methods described in subdivision (a) is utilized.