That sounds pretty corrupt. I've recently commented that countries with lower corruption perceptions probably have more corruption, and New Zealand is one of the lowest.
Unless you're some kind of competitively approved supplier that's chosen by default because you consistently do good work.
Why are you randomly wanting to go to an airport to measure sinkholes to calibrate a device? Why can't you make an artificial calibration sinkhole for your sinkhole meter, why do US airports have sinkholes, and why do you expect the airport to pay you for calibrating your sinkhole meter?