Re the MEL Holiday Inn outbreak. To be fair, the same nebuliser driven outbreak (assuming that's what happened) could have happened in any other state undertaking hotel floor Q ( NT, not looking at you
). Personal baggage from your flight is certainly not searched in WA. Had he sick man arrived into Perth with his nebuliser, the same infection would have happened to a similar number of people and they may have been worse off with (until last week) no community mask wearing and limited testing.
SOPS - if you read the fine print of most the states, such exemptions have always been in the fine print. I'm not as intricately familiar with SA's as I have been with every other state, but I'd be surprised if it was different.