Great question. I would definitely allow it with a student. The most common problem is a lazy arm too close to the body. If you re-analyze the videos in which you notice that my elbow is high you will see that I am playing on the lower strings. Note that on the above example the man is playing between the E and A string. Your elbow should be lower on those strings. Another factor for the height is the angle in which you hold your violin. 

To know if your elbow is at the right height analyze your wrist angle and don't allow it to be bent too much. A bent wrist is weaker than a straight one. Also you need to take advantage of the arms weight to be more relaxed.

The elbow should follow the contour of the strings unless you are crossing strings quickly such as in the barriolage bowing done here in the Bach Prelude:

Sounds to me like you are doing it just right. Your right wrist should have a comfortable angle and can be slightly bent but not too much. To give you an example, try using your fingers when your wrist is bent. Can't do it can you?