I checked with one of my Californian Valley based friends and he said he had never seen or heard of it happening and there are hundreds in the geek community around there. Probably a twitter fable made into an urgent 500 word homework item.
As with all these things, possibly based on an unrelated statistic that's then used to carry an entirely different message. California is about to ban the sale of small ICE devices like lawnmowers, so it may be that there's been some uptick in sales before the ban comes in. I don't know if it applies to generators though.
