I don’t think Bill was meaning that Trimix, wreck diving and Cave diving classes are scams. Sounds like "advanced diver" or "master Diver" is what he meant. I agree that you don’t need to be called an advanced diver or master diver. Has never helped me one bit. If you want to be a Trimix diver, go learn form the shop to be a TriMix diver. If you want to become rebreath certified, then go take rebreather. But "advanced diver", yea that’s a scam.