As to contact tracing - the federal government here has asked Australians to download a COVID19 app which keeps track of the user's movements and then enables the government to work out when the user may have come into contact with an infected person. So far about 5-6 million people have downloaded it and signed up.
I am always a bit apprehensive about the collection/security of data with respect to initiatives like this, but I guess Facebook, Apple and Google already have access to this information if they wanted it. You've only got to check your "System Services > Significant Locations" data to know your personal iPhone is perpetually recording where you are (and with greater precision as I understand it).
I am not sure such an initiative would ever fly in the US given the skepticism with which the government is viewed among certain segments of the population, but it seems like a better plan than requiring business owners to write down the names of people who enter their store.