Guys and gal, I agree very much with you all. The industry is not like the feudal Japan where the Samurais (DM/Instructors) have followers, and all of them serve under the Feudal Lords (Dive centres/Dive shops). Anyone steals or renegades are likely to be prosecuted or relieved of their heads.
Divers are consumers, and consumers have the right to shop where they like, take lessons from whomever they fancy. The choice is often made out of the convenience, ease and financial capabilities of the diver. Very often, we see special bonds forged between Instructor and students, or DMs and divers because of some reason or the other, but that doesn't mean the diver is not free to make his/her choice the next time they take lessons..
Its is all about MARKETING and customer/client retention. Take the effort to do something extra, make special effort, or some plus extra for your customer to show you care, and you like them to be your customer again. Do marketing programs, special loyalty programs for the customer to return back to you eg. if they take DSD with you, knock off RM50 when they do OWD with you. Or if they did OWD with you, knock off RM100 when they return to do AOWD with you. Or do special trip for your OWD group alumni, etc..
It is, however, not ethical if a dive centre/dive shop retain your services to teach their customers, but after that, you get them to sign up advance courses with you. Bear in mind that when they retain your services, you are their agent, and any deals between you and their customer, remain as so, as long as you remain or choose to remain as an agent to the dive centres. If you decided to renegade and become a "ronin" you should advise the customer of your status, and refer them back to the dive centres. I know it is a tricky situation, but I believe it is the ethical thing to do.
Dive centres/shops should realise that having a database doesn't mean the bond is exclusive. Database should be described as mailer database, not customer database. If you can't retain the customer by means of a contract or an agreement to make them a paying member of a special group, then your "customers" aren't really yours. They are just divers, free to make their own choices. Your premises is your territory to capture the customers, and if the ronins recruit in your premises then you can jump on them and ask for their heads.
Instructors/DMs/Dive Centres/Operators should be aware of contracts and agreements, and what actions constitute of a contract and what are agreements, signed or not. They should be aware of recruitment ethics as well. Respect for your fellow samurai makes all the difference. If you are in their territory, make courtesy calls, and tell them the intention of being there. If you are just there to enjoy yourself, don't tell anyone you're a samurai, just act normal. If your help is needed, then please have the courtesy to tell their customers that you are there just to help out.
I really think the industry is big enough for many to earn their living, just as long as they can work together, respect each other and above all, don't let greed take over. Mahatma Gandhi said " the world is enough for everyone's need, but not enough for everyone's greed"