and this is reply I got:
"No, it is not mandatory in California for drivers to sign organ donor in order to renew their driver licenses. In fact, California passed a law in 2019 that makes organ donation the default. This means that unless you specifically state that you do not want to be an organ donor, your name will be added to the Donate Life California Organ and Tissue Donor Registry. You will still have the option to opt out of organ donation, but you will have to do so explicitly.
The law was passed in an effort to increase the number of organ donors in California. There are currently over 100,000 people on the waiting list for organ transplants in California, and the number of people waiting for a transplant is growing every year. By making organ donation the default, the state hopes to increase the number of available organs and save more lives."