Unauthorized Persons (Education Code, §37.105)

A school administrator, school resource officer, or school district peace officer may refuse to allow persons to enter on or may eject a person from property under the district's control if the person refuses to leave peaceably on request and (1) The person poses a substantial risk of harm to any person; or (2) The person behaves in a manner that is inappropriate for a school setting and: (a) The administrator, resource officer, or peace officer issues a verbal warning to the person that the person's behavior is inappropriate and may result in the  person's refusal of entry or ejection; and (b) The person persists in that behavior. Identification may be required of any person on the property.