Originally Posted by
Nayef
We could use the perspectives of US-AU/NZ dual citizens as AU and NZ have had ETA programs for a while without major incident as far as I know whether it's departing the US or not.
That's actually a terrible example, as AU/NZ both have rules requiring entry on their respective passports, and not permitting the grant of an ETA (or NZeTA) to citizens.
As a dual citizen of AU and NZ, cross country travel is a gigantic pain - have to have passports of both countries, and show both passports at both ends, because neither country can grant a visa to a citizen, but both countries must still validate right of entry. Sometimes you can wing it, sometimes it all falls apart.
Originally Posted by
Nayef
I don't imagine this will be an issue at all for US-EU dual nationals, just like it hasn't been for US-AU/NZ citizens
It may very well be an issue. Not necessarily an insurmountable one but still.