I teach at a small private school. My principal (new as of last year) has put a policy in place that does not allow parents in the classrooms to observe during classtime (parents are still allowed for parties, special events, etc.) She seems to think that allowing parents to observe is a breach of confidentiality for other students in the class. This is the 5th principal I've had at this school and she is the first to take this stance. Is there any validity to it?