For clarity, I have never captured GPS info and have no desire to. But I have a problem with this statement. If a service provider whom I am paying has restrictions they wish to place on the provision of that service, it is incumbent upon them to tell me ahead of time. Don't trivialize that responsibility. If you have not stated a restriction, I am perfectly justified to think it is OK unless it is illegal.
All I am saying is that if it is important enough that it would be a deal breaker for booking a boat if you couldn't capture GPS coordinates, then perhaps the diver should ask before booking.