Originally Posted by
master991
Passengers don't get checked by border officers unless they fly to a country outside Schengen (the UK, Ireland, the US, etc)
It may be problem for those who got their EU citizenship confirmed and registered, who do not posses an EU passport and live far from a consulate. ETIAS application will ask questions about possessing citizenships and if they declare EU they may not get travel authorization because as EU citizens they do not need one. Instead they need EU passport! And if they do not declare truthfully they may risk their travel authorization revoked once a check against databases comes positive. Those who had their EU citizenship never declared, registered will most likely be fine since their country does not have any record on them.
ETIAS registration will cost only 5 EUR and be valid for 5 years. An EU passport will cost a lot more than that and require in-person visit at a consulate. In-person visit, even just for renewal is required since EU passports require fingerprint (exception is the UK, Ireland and Denmark). Those fingerprints are used at ABC gateways. Some consulates are not existent in some states at all. For example, Poland has only 4 consulates in the US (Washington DC, New York, Chicago, Los Angeles). Do you think people will flock from Florida to DC just to get their Polish passport so they can visit their families in Poland once every few years? For US Passport, you just fill application, put in your old passport, check and send by mail.
Due to the US use of the US VWP use as a carrot and stick against applicable countries in the VWP or wanting in on it, getting EU passports issued at consulates is way more complicated now than it was 15 years ago. So the idea of just going into an EU country's consulate and getting the passport issued isn't guaranteed to be easy and timely even when living within short walking distance to the consulate.
Due to cost (direct and indirect cost) differences for getting some EU passports in the US compared to getting the same in the EU country of citizenship, a fair amount of dual-citizens of the US go to the EU and do their EU national passport renewals/applications while in the EU, even if it means flying into the Schengen area on just a US passport.