I am one of those teachers who encourage students not to have strong white's near the edge of the print, especially for beginners who's compositional skills may not (or may ) be very sopishicated.
However, compositional rules are not carved in stone and if the images works, it works, regardless.
I have a student who has been working on a series of portraits that i feel are much too contrasty. During a recent discussion about this, she comment that she admired Richard Avedon, which was a great piece of important information as to the direction she was striving to reach. So rather than to continue pushing her to "change" her vision, I said, ok , let's take his style and work see want you can do to recreate that type of image.