Ostriches actually don’t bury their heads in the sand, the myth started when people saw them moving eggs around in their nests, but not seeing that they were moving eggs.
Indeed. But hobbits do bury their houses in hills, of course.
It is unfortunate that people are starting to think the virus is gone just because there are no new infections. People who have it still have it. Countries can open up if no one has it anymore, not just if there aren’t new cases
That's why the phasing is so important. Make sure any latent infectors are still not
licking other people's eyeballs without good reason (and bleachy eye-baths afterwards if they have?), and scale back the interdictions while (in the lucky position of having no huge outbreaks) jumping on any new suspected case with all the capacity you have for testing, contract tracing and then contact testing and onwards as required.
The (I bet it won't happen) promised 100k daily tests for the UK is currently aimed at Key(=Essential) Workers outside the NHS (after the patients and workers of the NHS have been sufficiently satisfied) but there's a lot of us in the potential reservoir outside that scope. If we were in the NZ situation, imagine even a fraction of the current capacity being used on anyone who just wants to be sure their dry cough is just something mundane (or non-infectious, but they could happily go to the hospital if it's a sign of something needing a biopsy to rule out cancer, etc) or their sneeze was due to an allergy.
It's the not knowing that has meant most rule-breakers have ignored some lockdown restriction or other (I heard a figure of 9%, the other day, which is a lot!) whereas if they tested positive - while feeling Ok and tested at all only because they were in contact with someone else tested/symptomed positive - and can be trivially supported by friends/relatives (who are themselves now sure they could do another shopping trip any time they need to required, because they're clear) for a requisite period then perhaps they will do so. Right now, an "infective but well" person might be the one doing the shopping for several households who have (initially) less reason to keep at home. But nobody knows of this.
For the same reason, any regime out there that is holding back on testing because "it's not counted if it's not been tested" may end up with zero 'cases', but are actually causing more of a problem than if they were adding thousands of cases per day (and even a number of positively attributed/associated deaths) but then using this knowledge properly to quickly reduce forthcoming days' figures.
But I'm sure that's just common sense, but a litte bit "armchair simulation" and the Real World™ still is a bit more complex.