From the School Handbook:

What do I do if I have a concern regarding a student/s who is not my child?

At times parents may become concerned about the behaviour of other students and, in an effort to resolve the situation, approach the student concerned. However, under no circumstances are parents to approach other students when trying to resolve an issue. Always seek assistance from the school. Incidents such as this can very quickly lead to reportable Child Protection matters that have to be investigated and reported.

It is also good practice to seek assistance from the school when you have a concern rather than approaching other parents about school related matters.

Always think about what you would do, or how you would feel, if another parent approached your child or confronted you about a matter where you were not fully informed of the details.