I also know for a fact that many unassuming buildings have gigabit ethernet drops that connect directly or semi-directly to 60 Hudson or 111 8th Ave. Probably wouldn't be able to get access without some serious contacts, though.

Most of the co-working spaces I've worked out of have horribly inept people in charge of their network allocation. They use older WiFi routers that have trouble with packet collisions. They provision a 768k DSL line to serve 20 coworking spots.

As recently as two weeks ago, about 16 people overloaded the internet at a coworking space I was visiting. Someone else (not affiliated with the space; the space employee didn't know how to do this) mentioned that they'd initiated a dhcp reset and a couple minutes later everything was back. When I asked him how he knew the router password, he said: "Oh.. they were just using the factory defaults." TBH, I wouldn't want to conduct business over a wifi network whose router was using the default admin password.