@Parsifal; in an earlier response to you I commented "...
Government regulations imposed on Victorian public schools means that 'procedural fairness' is not optional and that taking knee jerk actions in response to a gesture such as a fist pump can easily go belly up. ..."
Therein lies my answer re teacher conduct to which I'll now elaborate - I assumed you understood 'procedural fairness'.
The overwhelming majority of the time public school teachers conduct themselves professionally and with dignity. On rare occasions they need little more than a reminder / clarification and in cases where meeting expectations proves challenging for them they're provided with peer support, mentors etc.
If necessary they're provided with official written notices, a copy of which is placed in their official files. In cases of serious misconduct disciplinary processes are invoked [these are very specific and very detailed and can lead to dismissal and reference to police]. Responses to allegations of sexual assault include immediate suspension pending investigations.
Responding to members of the community is somewhat different and of course governments prescribe in considerable detail how teachers and principals are to manage and to respond when interacting with students - any teacher ignoring curriculum guidelines is on shifting sands and even open themselves to civil actions by parents / students.
Cheers!