Re: Visibility over Bluetooth
The generate and transmit random ids which are kept on the phone until someone tests positive, receives and activates their account at which point their ids for the relevant period are distributed to every phone who check the list against ids they've received. The hashing has been reviewed but, as with all these things there remains a slight risk, which is why some journalists and lawyers have asked for some exceptions.
BTW Bluetooth is only entirely invisible when it's disabled, which is why it's used in some shops for footfall detection – there's not a lot of identification you can do without people logging in: wifi and IMEI's from nano cells are more useful there.
Biting the hand that feeds IT
