I don't like it.
I'm all for tree hugging, cleaner air and whatnot, but that is moderated by my car guy ness. Really, how many 30 year-old cars are there out there polluting California? I can't imagine too many.
Rather than have some catch-all 30 year-old car legislation which supposedly plans for the future, it would be simple enough to phase this in once cars with some kind of emissions controls are getting to be that age.
If you look at pre-emissions-regs cars, they have no emissions equipment. There's no way you could get them to pass a sniffer test without at the very least retrofitting them with cats and in most cases converting them to electronic fuel injection.