Actually, this is one of the best ideas to come along, and one I have wondered why it "hadn't been done yet". The benefit from this is CLASSROOM DISCIPLINE (i.e. when teacher tells the parent that little Johnny has been mis-behaving, it is no longer his word against Johnny's--teacher HAS THE EVIDENCE ON TAPE), and in fact the very idea that mom and/or dad might be "tuning in" during the day will have the same effect on little Johnny that the presence of concealed carry licensees have on crime.