So once T&T is up and running and you get a notification that you have been in close contact with someone with CV19. You could be bleeped all the time especially if you are meeting your family which I believe is one of the highest risks and one of them has it Passing someone within 2 metres in a supermarket has little risk.
If for example its the winter and you are due to go on holiday, get married, go to a funeral etc and you are told to isolate then why would some people even get the app if they thought they would be stopped from doing something pre booked/arranged.
I see the younger people even less likely to have the track and trace because even if they had it they are likely to have symptons.
Or do we think its likely that its only with severe cases with a huge viral load given to you that will result in you being asked to self isolate.
I work at home most of the time anyway so this wouldnt be a big issue for me (unless I was about to go on holiday - I suspect your travel insurance would not cover you for this scenario) but for others I can envisage huge concerns going forward.