My guess is that people are getting infected at the grocery store and returning home to infect their family. The lines at my local Costco are as long as ever. People are behaving as if Coronavirus spares them while they purchase necessities, as if it operates by some chivalric standard of warfare. Most grocery stores are doing little to stop this. News organizations and public officials are barely saying anything about it too, even though it is probably the most common inter-cluster infection vector at this point.