1) That would be difficult to solve. If we used position reporting, and considered an area infected for a few days after an infected person arrived, it would mo

1) That would be difficult to solve. If we used position reporting, and considered an area infected for a few days after an infected person arrived, it would most likely lead to unmanageable amounts of false positives. 2) Scanning is mostly just listening and waiting for other devices to send beacons. With one discoverable device nearby, it might take a moment to hear anything. With 50 devices nearby, you scan should be spammed with results. You might have missed a few devices if you were unlucky and moved out of range before they got a successful beacon through. However, in that case you could use second-hand proximity to find the "lost" contact through some of the successful ones.