When a student leaves your school...

[DennisBreene]

I agree completely. Most of the Grand Masters I know or have read about have a history of studying more than one style. There is always the possibility that when one of your students takes a different path he/she will return with aspects of the arts to share with you. The journey is always one of learning. Being humble enough to learn from anyone with something to offer will make your path longer and more diverse.
Dennis

There are a million different legitimate reasons for a student to leave a school. I would say, unless you've asked the student to leave for some reason or another, the most important thing to do is to keep the lines of communication open and avoid burning any bridges. Life is long and the martial arts community is relatively small. While a student might leave now, he may come back in 5 years or 10. You just never know.

For me, more than anything else, life is about relationships, and what we do is secondary to the people with whom we associate and the relationships we build with them.