George S. Ledyard wrote:
Those folks who maintain that it is not the teacher's business whom you train with demean the relationship between the teacher and the student. Anything which has to do with my student's training is of concern to me. They are welcome to train any way they need to but if they lie to me or go behind my back they are clearly not students whom I can trust and I will not invest in them. If you feel that you can't tell your teacher anything about what you are doing with your training then you need to find a new teacher, not dishonor yourself by becoming a "sneak".
I hope you have this in your dojo kun too. A common day teacher is not a Psychologist in which you need to pour out your entire past, present, and future concerning anything. As an instructor I am there to teach, guide, and be a friend. If I have done my job correctly, my student would tell me.
If you have done your job correct and you have earned the respect of your students, they will be open and forthcoming with you anyways. I for one do not think just because I am called Sensei that gives me the right to dictate anything of anyone. I still must earn the trust of my students and vice versa. Being there before them does not make me a God in where I command anything.
If a student feels they want to tell me, fine. If they feel they do not, fine. I will not make character judgements of my student because obviously if they do not tell me, it is because I have not earned that trust and I need to accept that, or change it.
A real teacher that is involved with their student is going to know regardless of an open statement. A teacher that is just there to bring in money will not see the students change or growth in the arts, or care to notice. So if a person chooses to keep it from their instructor, so be it. A real instructor will notice the changes anyways.
On another note, many people are not close with their instructors. My true instructor and I are very close to this day. We ate dinner together, we went to recreational things together, I called him during ever changing things in my life (family deaths, divorce, school guidance, martial advice). He was a true instructor. He guided me in life, not only the arts. Out of the fourteen instructors I have had in my 20+ years experience, he is the only one who I would call an instructor or true Sensei. The rest were superficial teachers sharing their knowledge for money. Most instructors that are in it for money, could care less about you. They care that you return to help them make their lease. This is why I say be careful of who you learn from. Now I am not saying you can not learn from superficial teachers, but why feel an obligation to them that teach for money only. If you are close with your instructor, then you wouldn't be asking if you should or should not tell him, you ALREADY would have.