The only issue I could see is it maybe could fry the metal oxide varisistor.
When I converted my evse from boring US 120v power to use 240v US power I had to remove the MOV surge protector and install my own.
The control transformer may get hot running the slightly higher NZ voltage.
But if everyone is doing it is probably fine.
Do you know what the 230v power there actually reads on a multi meter?
More than likely they are using 300v MOVs on 200 and 230v systems.
I did not have to replace my control transformer because in the US we use 120/240v center tapped transformers. So all I did was run transformer primary wires from one of the lines to ground. So the transformer still gets 120v power to it.
This is not really allowed but oh well.