@izogi: imagine a tourist getting at the airport, passing through security about an hour before the flights departs, just to be told you can't leave unless you pay that $300 fine (or whatever). Yes some people would pay, but some would be "I'm not paying", or more likely "I just spent all of my money at the airport shops, and don't have anything left". Now the guy already checked in his luggage, it's possibly already loaded in the plane, at this time the plane is supposed to wait for the passenger as he already checked in, and he is in the airport. Now if he's not in the plane, it needs to be delayed so that this passenger luggage can be unloaded. This simple delay of a few minutes already cost thousands of dollars to the airport and the airline. Ah and I'm not even counting the fact that while the guy is held up at immigration point, the immigration officer is also stuck there, making the line of people waiting longer. Probably needing to open another counter, costing some overtime. Probably needs to have a security guard because the guy is getting nervous, which is quite likely as this is a stressful situation…
Now the guy is stuck in the airport, doesn't have money/doesn't want to pay for another flight. The airport is closing down, but the guy can't enter NZ again as his visa has just expired. You need to get someone from the embassy, someone from immigration, maybe issue a new short term visa, spend hours to sort it out. Worse case he can't/won't pay for a new plane ticket as he knows NZ will have to eventually. NZ govt will now have to pay for a plane ticket, after involving embassy, courts etc., costing thousands of hours of work, and dozens of thousands of dollars, for what, cashing on a $300 debt?
Not worth it.
It's just like when you fail to pay a $200 gas bill. They will bother you with letters for a while and give up after a few months, it's not worth it to pay a lawyer to get you to court over a small sum.
If you are looking for more money, maybe you should write to MPs about reducing the budget of tourism NZ no? Tourism NZ budget was raised by $30M 2 years ago, and is now about $120M/year. So like what the govt is doing here is spending money to get more people to visit NZ, and then complaining that there's too many people visiting NZ, and they need more money for that… Money that is currently spent on getting more people here… That just sounds like a BS excuse to raise fees. And the price for kiwis will probably go up the same way too…