NHS Covid-19 app: Why are some teachers being told not to use it?
"I have received a message from a teacher in north-west England who wants to remain anonymous.
Triggered alerts
This person downloaded the app on the day it was released and then, last Monday, tested positive for coronavirus.
As the test had been booked through the app, it then triggered alerts telling three colleagues at the school to go into isolation.
But then, according to the teacher, the secondary school's business manager told the three people involved to ignore the messages and delete the app if they felt they had not been within 2m (6ft) for at least 15 minutes."
https://www.bbc.co.uk/news/technology-54465356