Australian states investigate COVID-19 spread in quarantine hotels

If people do not have the virus, there is no point in quarantining them.

The entire reason for quarantining people is to ascertain if they are or are not infected. Incubation periods for covid are factored into the length of time for quarantine. People who test negative on day one are not necessarily virus free, they may test positive on day three or day five or day ten. That is what quarantine determines.

They were probably infected by a hotel worker, asymptomatic cases existing in the local population.

The nationality of arrivals is irrelevant. Test all passengers and crew before they get on the plane with a reliable test (not the quick ones).

If people do not have the virus, there is no point in quarantining them.

In a pandemic, hotels are best avoided - they represent an increased threat of contact with the virus. Self-catering allows you your own bubble.

These quarantine "hotels" were never designed to be medical isolation facilities and as such can not be expected to be effective in completely eliminating the threat of spreading covid. Perhaps each states capitol city needs to have purpose designed and built facilities for such times and for the rest of the time be government run cheap accommodations to pay for maintenance and upgrades over time.

Australian states investigate COVID-19 spread in quarantine hotels

Oh jee. And these geniuses in the AUS government are surprised? Of course the virus spreads if you stick people close together in a tight locations and don´t allow them out. Maybe next they think of cruise ships?

Putting a bunch of people in the same facility, some of whom may have the virus. And then being surprised at its spread?

Authorities fear guests who tested negative at the end of their NSW hotel quarantine and were allowed to leave could have already been exposed to the virus, raising the risk of it spreading in the community.

Isolation as a measure to stop spreading depends completely on this to be done properly, because of that failsafe mechanisms are also a necessity. it is extremely fortunate that in this case the system did not just assume blindly that isolated people cannot become positive while in isolation and instead tested also at the end of the quarantine.