So all I can find regarding RFID law is about actual forced (or coerced) implantation of an RFID tracking device.
"a person shall not require, coerce, or compel any other individual to undergo the subcutaneous implanting of an identification device."
They do define “subcutaneous” as meaning "existing, performed, or introduced under or on the skin." So that would cover something attached to the wrist. But, they also very specifically say "'require, coerce, or compel' includes physical violence, threat, intimidation, retaliation, the conditioning of any private or public benefit or care on consent to implantation, including employment, promotion, or other employment benefit, or by any means that causes a reasonable person of ordinary susceptibilities to acquiesce to implantation when he or she otherwise would not". They say nothing about voluntarily choosing to use one. It's like ozone generators. They are not legal in California only if they are sold as "air purifiers". If they're sold as what they are (potentially toxic if not used properly ozone generators), they're 100% legal to purchase and use in California.
I mean we are the state where we put up signs even at Disneyland saying it might cause you cancer
I would take this to mean as long as MBs were not a requirement and rather a volunteer situation (one which was not forced), that they could be implemented. The Premier cards have RFID in them and they're allowed in California (despite not being used in California. I've seen posts from some that the some DLR PhotoPass CMs have the technology to scan the RFID chip to attached photos rather than the QR code. Even my passport has an RFID. Hell, my cat has an RFID implanted in her skin (but they're allowed for pets; her RFID does transmit personal information of mine, however information I have volunteered to have available).
Perhaps we could get just the pucks in DLR. It would circumvent the "on skin". Owning one could come with a lot of the fun legal talk that informs people what they are agreeing to (and one could just unlink it to remove any of the identifying information; essentially to "turn off permissions"). They don't even have to have automatic photos from rides implemented (which would further get around the scanning part of the law). I had to more than once at WDW (because I didn't have my MB with me to scan at the tap points) hunt down a CM to get my ride photos put on a PhotoPass card. But they could put in something like that (or not at all!) for ride photos.
And as long as they weren't required (which they are not required at WDW), I still don't see an issue. They are not FP+ and there are definitely ways to legally use them in California.
I can see, however, Disney not believing there's enough profit in bringing them to DLR where they would be more limited in function both due to nature of the park and laws to be mindful of. Which is sad. Or maybe not. Maybe it's a good thing I can't drop money on collecting these things as they would gather dust from how little I go to WDW compared to DLR. Thanks for saving me money, Disney?