customs and immigration: how do Australian entry officials verify health and if the person is free from conviction?

Assuming you travel by plane from Germany to Australia and have an electronic visitor visa for tourism or business, how would the officers at the border verify?

1. that you have no convictions and

2. that you are mostly healthy (without tuberculosis, etc.)?

The websites where you get an eVisitor visa do not mention any documents you have to provide to prove the above.