That is the same for ANY adult. Any adult witness (to the actual crime or confession) is enough for an arrest of a juvenile. Any private citizen adult can question a juvenile and then call the police to turn them in for an arrest. They do not carry the same weight in court as a confession to LE and are not considered the same.Happens all the time. School officals act on statements from students.
They call in LEOs to act on student statements to avoid the "rights wavier " forms or question the student in front of the LEO to avoid it.
Have you had a school call and not acted on an officals statement to you?
Read this article. http://www.dphilpotlaw.com/html/interrogation_of_juveniles.html
The school official CANNOT act on behalf of LE to "get around" the waiver. If they do, any statements are inadmissible in court.