Disagree, the people not checking in understand the health order (its not actually a law, but a law does enable health orders to be issued) applies to them but are choosing to disregard it it because the information being collected is no longer being used for the purpose it was when the aps were introduced. States are no longer publishing lists of exposure sites with times, and since switching to notices in history, NSW is ignoring the check out times (which were previously considered) and just pinging everyone there within 24 hours, even if your visits were 12 hours apart.
They are accepting the risk that they could get fined (in some states) but given the business then also gets fined, businesses wanting to avoid this scenario would put a staff member at the entrance to ensure people are checking in. NSW removed the need to check in at low risk venues like supermarkets before reintroducing (compliance was much higher before it was reintroduced). Interestingly none are providing manual sign-in anymore, so they also cant penalise you if you left yoru phone at home (only the business).
They arent expecting to be granted an exemption.
Anyone who ever crossed a road against the lights, walked their dog off lead outside their own private property (except in an off lead dog park) or had a single sip of alcohol before they were 18, driven 1km over the speed limit has broken the law. That doesn't mean authorities don't enforce it when the opportunity presents.
International border entry rules are policed for all entrants. You can't avoid passing through immigration, the onus ins on the individual adult (not their agents) to ensure they comply with entry criteria and provide accurate information.