So Doc where do you draw the line?? Does every c-card expire without use?? Do you have to recert Nitrox? What if your AOW and haven't dived? Master? Who's going to pay for all the new c-cards with expiration dates on them? Wouldn't you have to do away with the honor system if expiration depending on diving?? Personally I think not all, but some and not a few would log a few dives to save themselves the hassle of taking a recert class and pay a fee. Maybe CA does have a law on airfills for scuba, but what about paintball? Like I said couldn't I walk in and get an airfill on a tank and say it's for paintball. Maybe I'd have a problem getting on a boat, but shore dives aren't regulated. Personally I think you'd be shifting some of the responsibility from the diver to the dive ops & LDS and padding the wallets of the cert agencies.
I don't think it's a bad idea, I just don't see how it would work. And as far as physical conditioning, you can't regulate that, if they could pass any agency swim requirements, there would be nothing you could do beyond that.
You say get the government out of the thread, and follow it up with "I, for one, would be in favor of taxes/licenses". I know what your saying but you can't have it both ways, by taxing or licensing your enevitably saturating our sport/hobby with government regulations, albeit state not federal, but what's the difference?