Just wanted to post an update. After making reservations with Scubatyme for a capt Dan dive I get a call on Thursday that the dive is cancelled and they are now doing an OWD because a group of people called him that were not AOW cert. I cancelled my reservation for 2 and rescheduled with south florida diving headquarters. I found that to be unprofessional to cancel at the last minute just for the money. But some people are all about that and not keeping a reputation....oh well.
It is very, very common in that area to have dive boats cancel dives at the last minute. Your cancellation was not the last minute. I have had them cancel by calling my cell phone while I was driving to the boat. I, too, disagree with that policy, and I have written about that on ScubaBoard several times in the past.
One of the south Florida dive operations, one that was recommended in this thread, did it to me enough times that I stopped scheduling with them. I used to use them regularly, and now I have not used them in a couple years. (I had a couple other problems that led me away from them as well.)
Last year I got on the boat at South Florida Diving Headquarters, the one you will be using, and learned that I would probably be the only diver that day. It would be just me and the DM. They had just gotten the cancellation calls, and since I was already there, they were going to run the dive anyway. (Then another guy showed up, so there were two of us.) The DM grumbled that the problem was that they don't charge for cancellations, so people sign up for 2-3 different boats and then cancel the others at the last minute. I argued that the problem was that dive boats cancelling trips at the last minute was the reason people were signing up for 2-3 different boats. That way they were probably going to get a dive that day. If the boats had a policy of going out no matter how small the group once they had reached a certain point (like 24 hours before), then people would only need to sign up for one boat. Last minute cancellations would thus be rare.
The operator I usually use when I go to Cozumel has a policy of not cancelling their dives, no matter how few the people. People sign up for it knowing that even if they are the only ones on the boat, it is gong to go. I believe that is one of the reasons that the shop is so popular that they never have to worry about not having enough people to make the trip worth while.