As modest as the NZ economy is it's still a hub for a few industries, and people still wanted to come for business purposes.
Also our politicians are deeply incompetent and were the only ones in Europe (AFAIK) aiming for herd immunity right off the bat, until they eventually ran the numbers on death rates if the ICUs ran out of capacity and realised it was a terrible idea.
2. Is your implication that the UK is so close to the mainland that the covid numbers are high due to people coming over in rafts? In that case the UK should have lower covid numbers because it has a much larger navy covering a the english channel, irish sea, and the north sea. Where as NZ has to cover the entire south pacific.
2. My point is that there's way more people entering, leaving, and going from A to B for whatever reason. Not trying to judge people, just stating a fact here.
But China knows how to do it, and they have much more density than the USA. You just need to be very authoritarian; e.g. marching people under guard to quarantine hotels from airplanes.
"seal" does -- whether any group is collectively capable of taking chain-of-exposure and its management seriously.
Make your island arbitrarily small and remote but have even a single person who's boating/flying or any kind of unmanaged travel outside the bubble regularly and you'll see infection overrun the island.
Pick an arbitrarily large city within miles of another on a shared continent with an unmanaged pandemic. Have it populated with people who are unified in careful contact management and they'll keep outbreaks scarce and small.