I don't recall seeing lanyards except for minors travelling alone, but don't always pay attention to these things. Best thing to do is probably contact Air NZ on social media and put it on their radar.
I see Australia is aware of it. Actually article was centred around Brisbane airport.
There was another app (forget the name) but was mainly cards saying "I have dementia" and other cards. Lanyards are more obvious visually which would be better than an app.