The article specifically states:
"The Bluetooth Address collected is not related to a specific device or an individual."
Which piqued my interest as I thought any sort of analysis between two points would require information relating to a particular device be collected, would it not?
Blip Systems' YouTube video shows that analysis of a particular Bluetooth device is measured between two points and the data is stored on a server and that data presented to the people collecting it.
Surely this is not a good idea, given that Google were recently stopped from doing pretty much the same thing globally with Wi-Fi network data.
The obvious response is, of course, "turn off your Bluetooth" but I think this is a case of implementing something wrong then telling people they can opt out.