[Retric]

Incidental contact is unlikely to matter in most cases. However, multiple people at different tables where infected at a restaurant from a single customer. So, it doesn’t take that much.

[eloff]

Or on public transport. New York's subway system was probably it's Achilles heel during this outbreak.

[dehrmann]

Except Staten Island had the second most cases per capita. Lots of the obvious NYC theories have holes where you look at places affected.

[jmull]

People who live or work on Staten Island used mta services, including subways, heavily.

[adrianmonk]

Maybe ferries cause the same kinds of problems as subways do.

[cozzyd]

Yes Public transport is probably the best use case for contact tracing. A combination of location history and fare card data will work for buses. For trains it's a bit trickier since you want to resolve that you're in the same car, and Bluetooth would work well in this case.