I have a metric now for interactions with strangers in San Francisco: Time to App. It's like Time to Crate in games, but here you time how long an otherwise interesting conversation turns to someone talking about their app.
Of course the people sending out invoices aren't having conversations! But still, almost surely there'd be a different distribution. More science, less film.
When I lived in Brooklyn, as gentrification rolled down from Park Slope, it became difficult to find a cafe that wasn't overrun by mommy gangs.
And many of us would just look at you with a "wtf are you talking to strangers for?" expression.