(Note, I almost never advocate new laws...)
Yes, it is California only, but note (from FatWallet):
I think the law will have a nationwide effect. Here's why:
Almost 75% of technology companies are headquartered in California, so all of them are subject directly to the law.
The law pertains to anyone who offers a rebate to a California resident, and that affects the remainder of companies (even though California would have a tougher time enforcing it's law on companies outside of its jurisdiction).
No matter, since everyone will have to comply with the California law where it pertains to California residents, they will not be able to differentiate them from residents of other states and so they will be forced to apply the terms of the law to everyone.
The FTC WANT you to report to them when you don't get the rebates using consumer protection laws! :)