If the operator turned down divers because he reserved space for them, he should charge, because he lost income. But if he did not fill the boat and would have had enough divers to operate anyway, he is gouging them.
I had a dive operation in Key Largo do this to me in very similar circumstances when I paid for an OW checkouts for a daughter and son in law. Conditions required their first OW dives be done at Jules Habitat (Keys equivalent to a quarry). We dove at Jules to be with them. He acknowledged that no one was turned away and that the boat would have operated anyway, but insisted on being paid per published policy because we could have gone on the boat.
I spent a lot of money there, two OW checkouts, three Nitrox courses, bought a dive computer and paid for 20 dives (not counting the four that I paid for but didn't get). They ripped me off, published policy or not. They won't get a recommendation or another penny from me. I steer people away from that operation when I can. Still hacks me off after three years.
I had a dive operation in Key Largo do this to me in very similar circumstances when I paid for an OW checkouts for a daughter and son in law. Conditions required their first OW dives be done at Jules Habitat (Keys equivalent to a quarry). We dove at Jules to be with them. He acknowledged that no one was turned away and that the boat would have operated anyway, but insisted on being paid per published policy because we could have gone on the boat.
I spent a lot of money there, two OW checkouts, three Nitrox courses, bought a dive computer and paid for 20 dives (not counting the four that I paid for but didn't get). They ripped me off, published policy or not. They won't get a recommendation or another penny from me. I steer people away from that operation when I can. Still hacks me off after three years.