Technology to the rescue
It just ticked the box of "do something and look busy" and any time you add the word technology in place, it must be good - right ??
I've never had a sensible answer from anyone about how bluetooth distance measurements could be 3D aware. If I'm on the floor above or below you and therefore "in bluetooth range", but well outside of any path that could involve transferring the Virus, then how would it know.
How would it understand the miles of plexiglass that were put in to protect people from each other - for example at the supermarkets and every shop you went into or when you are in a shop and someone is outside sitting on the bench etc. The same thing about being outside - how does it know compared to inside, which is supposed to be worse etc.
As it doesn't understand the real world, it can't give accurate responses and will always over estimate risk.
However, from a Govt. perspective, I guess it made people feel better that "things were being done" and it didn't involve doing a bunch of other harder things.
Personally, I've never installed it and have no plans to do so.
Biting the hand that feeds IT
