I would agree with having the psych do it. We had one done for DS at his preschool, and only notified the director(and provided all waviers etc) so that the teacher would not know who or why (just that the class is being observed). And we made sure it was an adult DS never seen so that he would not know it was him (the director was vague enough).
Don't all teachers, regardless of what they are teaching, expect that they could be observed randomly, even if just to evaluate the teacher? I can understand not allowing parents since I lived in some really major tiger-parent towns where parents would really be on attack for the most minor issues (and where they spent all their time trying to shove their kids ahead of everyone else), but the school should allow professionals to observe... otherwise I would question what the teacher is doing behind that closed door. For something like this, I wonder if the principal is the person to talk to about observation rather than the teacher.
