Vi Hart is a mathematician and technologist and she has been working (with many other experts) on a report called "The Roadmap to Pandemic Resilience." She absolutely schools me on how bluetooth tracking and contact tracing actually works. And she also makes it clear that right now isn't a time for picking one strategy, it's a time for exploring all of them without knowing for sure which ones are going to be most helpful. 

But one thing's for sure, all of this would be much harder if it happened even ten years ago.