Sorry for this "license" scam! Canada was the first to have an operator knowledge proof card. Washington State being so close to BC, copied us and so on.....
I kind of laughed on RD's site when someone who claims to be law enforcement said California can't legally do this program due to shared waterways on the River, etc....
I imagine California copied us (Canada) and Washington. Non resident boaters are exempted from the law. So if you are an Arizona registered boat and owner. No card needed. CA boater and registered there. They can enforce the law on you, even on shared waterways.
Its not a big deal. Its an easy knowledge test and not a license. Here and in Washington. Completing a rental checklist is enough to be legal if you rent a jet ski or boat.