https://www.siliconvalley.com/2022/07/13/california-blocks-gun-sales-to-those-at-risk-of-breaking-law/

SACRAMENTO — Gun makers and dealers in California will be required to block firearms sales to anyone they have “reasonable cause to believe is at substantial risk” of using a gun illegally or of harming themselves or others, under a new law that Gov. Gavin Newsom announced Tuesday that he had signed.

It’s a subjective requirement that goes farther than current background checks or prohibitions on selling guns to people prohibited from owning them.