are there ethical issues if you put Surveillance Camera in School?

Hello guys.. just wanna know how does surveillance camera affect the students and teachers privacy? is putting a surveillance camera with audio in it., per class room will violet ethical issues of students or teachers?.
purpose: Monitor Employees and so as control defiant students, vandalism, thief etc…

Surveillance cameras in public areas of a school or business do not violate anyone’s right to privacy.

I can see you doing something with my eyes, or I can record you doing something. How is there a difference?