They didn't ask because they didn't think they'd be taken. People's perception of closures impacts what they do perhaps more than the legal enforcement.
People are still being allowed in and out of Melbourne with valid reasons. "oh they'd never be let in anyway" is a medical board review, loss of medical license, probably worse kind of situation.
My understanding is that you can travel, but you'll be in 14 day hotel quarantine at your own expense.