Re: Proximity
The research from Singapore, which was one of the first to adopt such a system, says they were tripped up by the extremely variable power outputs of Bluetooth devices so that signal strength alone isn't sufficient, which is why you need something passive like the RFC protocol.
Worth noting, in passing, that the tracking in Singapore doesn't seem to have helped that much. But that's what you'd expect with a highly infectious epidemic that's had time to spread.
Biting the hand that feeds IT
