Sounds like a good way to have every milk container say "rBST free, from cows raised without hormones!" Which could also be stated "farmed in accordance with California law."
Yeah, in this case, I'd rather have the former... Since I'd assume the latter? Maybe that's me.
And, to be clear— I don't want to be dismissive of the importance of govt regulation! It's just that working out the marketing opportunities can happen much faster than effective regulation.