Graham. wrote:

I thought this was a passable piece of journalism.

https://news.sky.com/story/coronavir...ntial-11980579

If only it wasn't using one of those "scrollytelling" web styles ...

I think these apps either rely on a centralised databse that would be
every search engine's dream or defeating bluetooth MAC address
randomisation (why do you think every shop offers free wifi? to defeat
wifi MAC address randomisation)