Riverwalk
^It would only be following you registering your presence at a venue^
This is incorrect.
If someone tests positive they are contacted by Track & Trace and have to provide details of people they've been in contact with.
So if you have lunch with a neighbour and she tests positive, you may be contacted.
Very true Riverwalk, I had an outside lunch with a group of friends, one felt ill that night and tested positive in a PCR test. She was contacted by Track and Trace and had to tell them the names of the host and those sitting beside her. - luckily she also knew their phone numbers. These three people were then contacted and told to self isolate. Track and trace said that everyone else was fine as we were sitting further away. The process was very thorough with follow up phones calls to check they were isolating - only the household of my friend with Covid had to isolate, the other households were fine as they were not first degree contacts.
Incidentally my friend is in her forties and double jabbed with no underlying health conditions but was still very poorly and spent 24 hours in hospital being monitored for breathing problems. Her breathing is still affected six weeks later.