Cities are weird beasts. I live in Midtown Atlanta and walk to and from work, I am also out and about sometimes in the evenings. It's one city at these times. But if I'm out late at night, every now and again I'm froggy for a late night walk, I see packs of people just hanging out. I have no idea where they came from, where they live, Midtown is an expensive place, or why they feel like Midtown is a great place to bring your private outdoors party, but I don't encounter it unless I'm off my routine.

It's possible that open drug use might be happening right under your nose and you're never around to see it.