I have a quirky question that I'm forwarding on behalf of a client:

"My caller ID comes up with my number in NZ, but when I call someone in Oz it comes up as 'private number'. Why do you think that is?"

I've had her check ID blocking on her iPhone 8, but all appears correct. What am I missing?

It's not something I've ever thought about. Personally we have occasional phone contact (most is Whatsapp and Skype) with family and friends around the world and no one has ever commented.