Manicuring a lawn is expensive and serves no useful purpose, so most practitioners have disposable income and/or spare time, and care about keeping up appearances.
Putting a car up on blocks implies it's being used for spare parts, which is generally not something the well-off need to engage in (they buy new and use professionals for repairs as needed), and having one on your front lawn in particular implies that you value spare parts more than appearances.
So both are reasonable proxies of wealth, and wealth correlates inversely with the kind of violent crime you could detect with gunshots.
Edit: you added the correlation bit after I replied, but why do you believe that to be the case? If you have more police in an area, of course they’ll hear more gunshots there. That doesn’t necessarily mean there actually are more gunshots.
What you’re actually saying is “poor people need more policing”, which is A) offensive and B) counterproductive.
So let me get your point straight: your worry is that since wealthy areas have less sensors gun-crime in those areas will go under reported?
Idk about your neck of the woods but where i live if I hear a gunshot I call the police with a high probability. If i see someone brandishing weapons i do the same. And of course i call the police/emergency services if i see someone with a gunshot wound. These all create the statistical evidence independent of the sensor systems.
Let's imagine a city divided in two halves of equal population. West City is poor and has a high crime rate, East City is rich and has a low crime rate. Should police resources be allocated equally to both? How about public health facilities or welfare payments?
Enter my teen years. I had cars up on blocks in the driveway. My poor mom!
The causation more likely goes the other way: When an area gets the reputation of being higher crime (because of reality or because of bias from more police saturation), that area becomes cheaper to live in, and poorer people can then afford to live there.
