Although I have the app and have been using it I do worry about how accurate it is going to be. To give an example, last Sunday myself and the wife went out for some breakfast at a cafe. I used the QR code to check in there but because we had our dog with us we were put in a separate annex to the main cafe bit. With the exception of the waitress, not a single other person came in there during the time we were present. Now the thing is, the rest of the cafe was really busy so if someone else in there at that time was subsequently tested as positive would I then be told to sef-isolate despite the fact I was basically in a separate room? (It hasn't happened by the way it was just something I wondered at the time!)