Yet FB today was full of relieved messages from people who had downloaded the app and discovered levels were "low" for their postcodes, which anybody with half a brain could have told them anyway!

Yes, that is indeed good news because false negatives are not really an issue. Therefore, what they got officially was indeed true.
However, they should not take too much comfort in this app. When the covid-positive rate goes up, the app will report test results that amplify it due to false positives. Today, I reckon that could be up to 20x
So they may feel secure at the moment, but it is a false sense of security.

I just hope all these gullible morons enjoy trying to pay their bills on 2 weeks enforced SSP. I'm sorry to sound vindictive but I do hope the sheeple start to suffer coz IT'S THE ONLY BLOODY THING THAT WILL WAKE THEM UP! 😳 😳 😳