That is the most common sense solution that I have heard.
It works on so many different levels. Divers are happy, the kids get hard cash. Have the kids supervised by the marine park who issue a badge or vest. Make it part of the orientation that the kids work for tips and suggest a rate per diver. I envision kids bidding for choice dive sites. God forbid, that a really good site gets taken away from a kid because of theft.
Vince, Pilot Fish, this idea can work. What makes it feasible is that the locals will be fully invested in the protection of divers rather than a few of them acting like predators. This idea creates a new service industry for low skilled workers and increases the interaction between the divers and the residents in a positive light.
I think it would totally work, and there are many historical examples to back this up. I believe the Mafia refers to this as "paying for protection".