I think it is to do with definitions around "casual" and "close" contacts.I just don’t get places like Bunnings not having it.
Every state seems to do different things, but generalising, I think - 15 minutes in the same spot makes you a casual contact, and 2 hours in the same spot makes you a close contact. (The more neurotic the state leader, the less time involved in those definitions.)
The definitions effect what directions are given if a venue alert is issued, I think, again generally - casual contacts must get tested and isolate until a negative result is received (up to 72 hours), but close contacts must get tested and quarantine for 2 weeks regardless of test results.
The problem with some places/venues/stores (and I am not suggesting or singling out Officeworks, as mentioned above) is that they are data harvesting, using private companies, for reasons other than contact tracing