The way they are doing contact tracing now is practically useless. They are publishing the locations of where some of the confirmed cases went and telling those who were there to "watch their health for 14 days". Does it mean those who didn't go to those places need not watch their health for 14 days?
And by collecting all these data of people going in and out of malls, restaurants and shops, what are they going to do when a confirmed case says he has been to one of these places? Contact every single person who went there that same day and ask them to watch their health?
In my opinion, they should forget about this high volume of data and simply drill in on investigating the movements and behaviour of confirmed cases or close contacts of confirmed cases. You put it very politely when you mentioned casual asking. The way they are doing it currently is not going to uncover any links when there is deception or illicit activities and relationships.
Not sure how this contact tracing works, but if I were to hazard a guess and stretch my imagination-
1. Date; 2. Time & Duration; 3. Location; 4. Close/Prolong contacts, Transient/Brief contacts.
After the first four points established in a chronological order, the possible contacts are traced then information is verified and cross checked to triangulate who are those who need to ring fenced.
Casual asking isn’t going to help when the folks have something to hide. Little wonder the hidden reservoirs remained hidden.