Are they going to make people wear a badge and go and paint signs on the outside of their houses so that, if they step outside, they can be fined?

I know a lass from Holland who has been self isolating since she came back to the country. She filled out all the necessary forms which nobody took from her when she arrived at the airport. She has stuck to the 'rules' just in case someone rang up to check that she was isolating, guess what, never received a call at all. She asked me why, if nobody took the forms or checked anything when she returned to the UK, she had to self isolate -----can any of my learned friends provide an answer?