This is a great law that I had never heard of.
Given that NYT and others don't actually follow this though, how can California residents enforce this?
From what I've read, NYT and others do follow it but only for those with a California address in their system.
Apparently the trick is to change your address and then attempt to cancel.
In the other direction, I'd be quite laudable if some Californian would put in a non-California address, attempt to cancel, then sue them when they refuse.