Illegal According to FERPA

A friend of mine who is a teacher informed me tonight after I shared about this teacher's practice of sharing the A grades with the class and commanding applause that this violates a federal law concerning student confidentiality.  The law is under FERPA, which I need to research, and prohibits sharing student's grades in the classroom.  So I emailed the principal and brought this to his attention.  He is looking into it.  I really don't want to get this teacher in trouble, I just want him to change how he rewards the A students to a way that is private.  After sharing this problem on Facebook, without revealing the teacher of course, I got a large amount of feedback expressing shock that this teacher would do this.  So I guess I am not too far off in my concern.  We shall see what happens next.