Striking a balance between acting upon legitimate safety concerns, and unduly alarming people, needlessly disrupting their lives, is a delicate business.
Underplaying danger and thus not taking appropriate precautionary measures runs the grave risk of exposing communities to life-threatening events.
For those whose responsibility it is, on the behalf of local, regional or national government, to avoid such scenarios, there is no comfort, or safety, in post-disaster debriefings in which the best evidence, the scientific advice, the expert predictions, were all found to be wanting or just plain wrong.
Safety first is generally a sound strategy in civil defence or other emergencies.
On the other hand, the perils of overreacting, without due recourse to that best evidence, invites "the boy who cried wolf" syndrome: public apathy, resentment and in some cases plain civil disobedience in the face of future crises.
As the waves attendant upon Sunday's tsunami dissipate - waves that never in any threatening or particularly visible manner quite hit Otago - others may continue to ripple in civil defence and police circles.
For as news of the supposedly imminent waves was being broadcast across the country on Sunday morning, it became apparent that there was a divergent approach from authorities in Dunedin.
While the stance of the police on the one hand, and civil defence on the other, might be equally defensible, it is less than reassuring for the public if the major organisations tasked with co-ordinating responses to such potentially devastating events appear to be singing from different song sheets.
On Saturday about 7.30pm, a massive earthquake struck Chile.
It measured 8.8 in magnitude, destroyed buildings, bridges and highways, and killed an as yet indeterminate number of people.
It also sent a tsunami racing across the Pacific at speeds of up to 700kmh.
By 12.38am on Sunday morning, Dunedin civil defence, under the stewardship of Dunedin City Council civil defence manager Neil Brown, had sent out its first statement referring to a "non-destructive" tsunami of 1m from 8.30am "at which time it will be approximately half-tide on a falling tide, so no damage is expected".
National civil defence alerted media, and by 7am Radio New Zealand National, as one example, was broadcasting nationwide alerts and warnings, and newspapers, such as the Otago Daily Times, had posted information on their websites.
The coordination between authorities and media outlets was much improved on that of a mere five months ago in the aftermath of the Samoan earthquake and the subsequent devastating tsunami.
Residents in South Otago and 60 campers at Hampden in North Otago were moved to higher ground.
In Dunedin, emergency response group manager Inspector Alistair Dickie mobilised about a dozen police as well as volunteer fire officers and surf lifesavers to patrol beaches warning people of anticipated risks.
The pattern was repeated nationally.
Despite this, some people steadfastly refused to obey instructions: swimmers flocked to Auckland's Piha beach, for example, determined to make the most of the hot summer weather.
A few surfers at St Clair ignored police advice and carried on surfing.
That "nothing happened" may have emboldened many of them.
But to an unsuspecting family on a beach with toddlers frolicking in the shallows, in certain circumstances the tidal surges that did eventuate could perhaps have proved life-threatening.
Insp Dickie defended his actions against claims of overreaction, saying he would "do it again if it happens again", while Mr Brown, who spent the night dealing with the issue from his home, similarly stood behind his contrasting low-key approach - which has been criticised in some quarters as inadequate: "We did what was appropriate in the level of risk, bearing in mind there was no risk of tsunami inundation in Dunedin."
He and civil defence turned out to be correct in their assessments, and therefore in their actions.
It would be a brave, perhaps foolhardy person to accuse the police of overkill.
There are, however, lessons to be learned from such experiences.
In this case, there was at least the appearance of a communication breakdown between the two camps - a wrinkle, perhaps, but one which, if not smoothed out, has the potential to spread doubt, confusion and indecision in the minds of the public.
In times of genuinely serious civil emergencies, that in itself could prove disastrous.
