Ultimately it's their train set and they can wreck it if they want. The staff who work for them have the choice to vote with their feet. As many have done, and more will.
The PNG Kina is not so bad, but having the whole lot taxed in PNG is a deal breaker. 40% gone down the plug hole with nothing to show for it, not even a warm fuzzy feeling that the money is going to do some good for the impoverished and bagerup country.
Whether all of that tax previously taken out of the pays ended up with the tax man where it should is the interesting question. No doubt more will be revealled about this in the fullness of time.