EWP use by contractors At the end of the day, it all comes down to managing risks and what is reasonably practical, and requiring evidence of appropriate competence to operate any equipment safely would be reasonably practical.
There are still many gaps in NZ's system, so PCBUs cannot expect to rely entirely on other PCBUs to hold up their end of the work - for many people, if they can get away with doing less, they will, and if they have successfully used those EWPs without any formal systems or qualification, they will just keep doing it until someone pulls them up on it. Since all PCBUs have shared responsibilities, either insist on appropriate risk management systems and practices, or find a contractor who will do the right thing. If a PCBU knowingly accepts contract work from a contractor who doesn't manage the risks, you are effectively taking on those risks yourself. In addition, every PCBU that allows the requirements to slip just makes it that much more difficult to manage other aspects of contractor work, making a rod for their own back.