Yeah that's fair, especially your last point. In a perfect pandemic-fighting world we could just have an app that did that, the decentralized model adopted won'

Yeah that's fair, especially your last point. In a perfect pandemic-fighting world we could just have an app that did that, the decentralized model adopted won't be that specific. It would be more something along the lines of uncle dave getting a notification. I share your concern on initial adoption, especially since I could not find hard data on places that already implemented apps. I would expect an initial rush and then a plateau instead of WhatsApp like growth as some people expect. As for your specific questions I can only offer a few points on two of them given what we know about the current plan here in Germany, that highly depends on the country and I honestly have not looked at how health authorities work in the US very much. > What happens if the app flags them as possibly infected? Can they call a hotline to give them information or is it just some automated crap they hear? The new vendors here in Germany were especially chosen with the argument that they are able to operate 24/7 human phone support. With the decentralized approach they'll get a lot of people flagged and at the moment it seems like the app would suggest to them to call up that number (or likely offer that as an alternative to the other established contact points). Those phone contacts could then talk them through the next steps or, should testing become too limited at any point, through an assessment if testing makes sense for them / voluntary self quarantining can be done / ... > It works using bluetooth. How much power drain on their batteries are they willing to accept? In centralized models as proposed by PEPP-PT/ROBERT(France) or NHSX(UK) there's a few ways explored to minimize battery usage on Android, the APIs on the iphone require the screen to be turned on for this use case and must subsequently be horrible for battery usage. The decentralized model that was adopted adopted by many countries is supported by Google/Apple as OS vendors with battery usage and interoperability with other Bluetooth usage in mind, I doubt there will be much of an impact (at least not any that would drive significant user numbers away from voluntary use).