The short answer is no. This kind of thing is a hindrance to growth because it is embarrassing to the visitor and may keep them from returning. This statement seems to be judgmental and critical, not constructive. The teacher was probably well intentioned but nevertheless this practice is harmful. Of course Sunday school teachers need to be trained in how to handle all kinds of situations. In fact, the pastor should teach, or provide teaching, to all teachers, and staff, as far as that is concerned, on a consistent basis, on how to work with peopleOne mistake pastor's often make is to assume that an adult should inherently know, or understand, how to deal with people. We cannot overstate the importance of ongoing training for all Sunday school teachers. Training not only deals with how to teach the Word of God but how to deal with the age of the person you are teaching. All age groups have similar character traits and a teacher must understand how to deal with a student in regards to their age characteristics.