You know, something bothered me about this thread from the beginning, and today it finally gelled . . . I think there's something not great about discouraging people from diving, WHEREVER it is that they dive. Diving is an activity that gets better with practice, and better means not only more fun, but safer. I'd MUCH rather see someone dive every weekend in a quarry, than save up their $3000 and do one trip a year. The person who hasn't been in the water for a year just isn't going to have good habits ingrained to the extent that the frequent diver does, and certainly won't have practiced any emergency procedures (which is not to say that everyone who dives regularly does that, but if you haven't dived, you for sure haven't practiced!).
I think we should celebrate quarry diving! As Mike's photographs show, it can clearly be great fun (not sure I wouldn't prefer a tour around Dutch Springs in that kind of viz to some of the OW dives we get in the summer in Puget Sound!) and it's great to keep people wet when they aren't lucky enough, as I am, to live thirty minutes from fantastic shore diving.