And that can vary widely! In my neighborhood we have an optional $100 per year HOA fee. It goes to planting flowers at the entrance, helping pay the water bill of the guy who lives at the corner and waters those flowers, and repairing the brick wall beside the street that cars keep crashing into. The HOA president collects those fees and runs the Facebook page to let people know when there's a crime issue, cars getting broken into or things stolen out of garages, stuff like that.

Ahh interesting. That still seems to be different than in europe. I am not aware of HOA being a thing on community level. At least in my country it's just a big lobby and legal organization. They help you with legal services if you have trouble for example with construction companies. I think the stuff that your HOA does is here handled by the municipality. You don't have to be HOA member.

My neighborhood growing up had a neighborhood watch sign. Nobody actually patrolled. I just assume it was a hotline for busybodies to call when they saw suspicious people.

Only time in my life I’ve ever seen guards posted at night was when I was in the military.

I could see it plausibly happening in an area with major rioting and wide spread civil disorder. Other than that, nope.