Scooters in California are required to be on the road (not sidewalk), operated by 18 year olds an up and operator wear a helmet. almost none of these are observed.in actual use

I think the answer is that laws should be changed so it is the scooter company that gets the citation and the fine, not the operator. That would incentivise scooter companies to put better controls in place as to location, verification of rider age, and providing helmets