Business people lining up to claim financial compensation after health authorities overestimated the seriousness of the Adelaide cluster because a pizza shop worker fibbed to contact tracers should take a deep breath and consider what could have happened.

The state should come out of lockdown by Sunday and restrictions have already been substantially eased. The inconvenience they have suffered in the past 72 hours or so is as nothing compared to Melbourne's 100-day plus lockdown.

Mr Marshall and his medical advisers were acting on the best available information. When they were told coronavirus had been picked up by a casual visitor to the pizza shop where a known COVID-19 case was working they "went hard and went early".

It was a tough, but defensible, call given the infected man's decision not to tell authorities he was an employee who had worked in close proximity with the other infected individual led them to conclude the virus was out into the community and spreading rapidly.

It was not until this individual, who police have said can't be charged because "there is no penalty for not telling the truth", was identified as a close contact that the experts realised the risk of transmission was actually much lower than they had first believed.

The lockdown was not a mistake or a bungle. It was a legitimate response to a grave threat to public health and safety made on the basis of what had happened in Victoria and the best available information.

The best proof the system works is that when health authorities got more accurate information they recommended prompt changes which the government acted on immediately.

Anybody who thinks the government's actions were over the top only has to look at what is happening overseas. There have been more than four million new cases around the world in the last week bringing the global total to 57 million. More than two million of these were in the US which has now reported almost 12 million cases and 253,000 deaths.

The virus is raging in India where the reported nine million cases are believed to be the tip of the iceberg and this week has been marked by violent anti-lockdown protests in France and Germany.

Just as many of the lessons learnt from the Victorian second-wave outbreak were used to inform the decisions taken in South Australia, what has happened there will, in turn, help the experts and advisers fine-tune future outbreak responses. It is important not to lose sight of the fact Adelaide did experience an outbreak clearly linked to failures in its hotel quarantine system, and that this grew to 25 cases in a comparatively short period of time.

It also became apparent over recent days that South Australia needs to step up its emergency outbreak testing response capability. Having people queued up for kilometres in heat wave conditions for half the day before being sent home on the basis the stations were about to close obviously isn't good enough.

South Australians did the right thing by turning up in large numbers to get tested this week. They definitely deserved better.

It would make far more sense to concentrate on addressing these issues than to start a blame game over what should, or should not, have been done. South Australia has dodged a bullet and it's apparent many residents are very grateful for that.