How can people leave their cars running unoccupied?

Different lived experiences and different locations, and different experiences naively carried over in to new locations I guess. Last week I left my phone on the table when I want to the bar so people would know the table was occupied. Because I live in an affluent area. (Not remotely in the countryside, in a major city infact.) Would I fuck do that in most areas. I'm not an idiot, I know that bad things and bad people can happen/be *anywhere* but we make risk assessments every day. I was pretty comfortable that the likelihood my phone would be pocketed would be tiny, because of all sorts of factors like the table next to mine having some goofy nerdy students on it and most people in the bar being 40+ and somewhat wealthy-looking. I think leaving a car running is slightly odd behaviour anyway because it takes 0 seconds to switch off the engine and remove the key (in my example above I was gaining from leaving my phone because I saved my table). But I wouldn't be too concerned leaving my car running in my area of the city, but absolutely wouldn't in some others. I grew up mostly in an area similar to the one I live in now (although have lived in some "worse" once since) and so if I was a moron I would assume you can just leave your expensive shit everywhere in *any* area, rather than having some common sense and evaluating your surroundings. If, on the other hand, I grew up in or had only lived in rough places I suppose I would be incredulous that anybody would leave anything expensive anywhere.