Up until about 2 months ago contact tracing in Australia was very effective. Contact tracing teams were able to trace who and where each person got infected. They were also notifying/testing/isolating first and sometimes secondary downstream contacts (up to 400 people in the case of one country town outbreak).
One of the infections was traced to a department store and the interaction between the two people was caught on cctv. They walked past each other and didn't talk. It was seconds.