Not just this area, seems like CA in general. Maybe CA has more affluent neighborhoods?
When I lived in Santa Barbara, I got knock on door. It was a County official, very apologetically telling me he had to follow up on complaint. Apparently, guy next door took offence at me running my tech-consulting biz out of house. County guy said everything's fine since I don't have store-front with customers coming and going. He even showed me map of complaints and it showed a ring of about 9 houses. Idiot next door had complained about EVERYONE around him! Can't imagine what trouble guy like that can stir up if he had whole book of HOA regulations he can scrutinise entire neighborhood with.
I go by live-and-let-live idea. As long as neighbors aren't preventing me from doing what I want to do, I don't really care what they get up to. And I try to do same. Is the complaining-guy doing weed in his car hindering my life in any way? No! So I don't worry about it.
Lady behind me called one time about my salsa-dancing party going a little late and loud. Sure, I moved it all inside and closed doors & windows and called her back to see if it's OK. I guess lots of people don't turn it around.