I've had a worrying experience today, with the damned thing! I was out in town with B when I suddenly had an alert in the notifications on my phone. It said "Possible COVID-19 exposure...."
I clicked on, and it took me to the app but there was no further message on it
A few minutes later I got a second notification saying " Don't worry, we have assessed your risk.... " so I clicked on again, and again no full message!
So I searched around the app and found a page describing the messages they send out, and my second message in full should have said "COVID-19 Exposure Check Complete. Don't worry, we have assessed your risk and there is no need to take action at this time. Please continue to stay alert and follow the latest advice on social distancing."
So why send the messages in the first place! It gave me a bit of a turn