Are there any airlines out there that realize that scuba divers travel to exotic locations with their heavy gear and have added dive equipment into the free luggage allowance? Golf equipment and surfboards already are common so why not dive gear?
That said, I have had a negative experience in a well known dive destination: Cozumel. Coming in with dive gear, I checked in my luggage and paid nothing extra--I was within the airline luggage rate regulations. Leaving, I had the same luggage, same airline, same flight-and they told me my bags were over the allowed limit, and I'd have to pay a $100 fee. After arguing for a half hour, causing a scene, and backing up the line, they finally let me through without an additional charge. If it happens again, I will contact the airline and file a formal complaint. I doubt that it would do any good, but you never know. However, it would be a good idea to arm yourself with airline documentation that states poundage allowed, and other regulations, so you can be prepared, just in case. I have also met a lot of surfers and golfers (I live in a resort location--Manzanillo, Colima--in Mexico). To my knowledge, they exchange a surfboard or a golf bag for the equivalent of one piece of luggage.
But you're right: airlines should treat scuba gear the same way they do golf clubs and surfboards.