Now, since I adore my daughter's school, I am not going to question the reasoning behind their titles. It's their system and I follow their rules without hesitation (such a good doobie, I know).
In martial arts academies, however, I believe there should be a different kind of verbal connection. There is a need for some distance between the instructors and the students. And truthfully, the difficulty is not with the children in the classes, it's with the adults.