Originally Posted by
KLouis
A dual EU/non-EU citizen travelling as an EU citizen (EU passport used) will certainly not need anything of the kind. Simple logic, though, also says that if (s)he shows his "other" passport at immigration, he'll be asked for an authorization. Also, if they model the ETIAS on the US and entry Aussie authorizations, they will not be bothering to ask for it when exiting the EU. At any rate, let's wait and see...
I'm thinking more about the mechanics of how this will work. A US/CAN citizen needs to enter/leave the US on their US/CAN passport. Because US/CAN doesn't have exit immigration, this needs to be transmitted to the government through the airline. Now the airline also needs to check that the person is eligible to enter Europe - an EU citizen would need to present their passport for that. The question is whether the airline can technically do it.