Schools and teachers have standards for each developmental level. As an educator, I have found most are fair, reasonable, and appropriate. As a parent I have found it helpful to contact the school and teacher(s) directly when I have had concerns about actions taken at school. I have found it helpful to hear both sides of the situation before getting overly concerned.
If you feel an action at school was inappropriate, talk with the school professionals to become acquainted with the whole situation. Work together as a team to devise a response if the situation should arise again.