Wow. That sounds like a pretty crazy hole in the ETIAS plan, and your comment belongs more appropriately as a child of the original's in regard to the following:

> - There is a separate dispute between EU and US, because US imposes visas on five EU states (Bulgaria, Croatia, Poland, Romania and Cyprus). According the EU law, all EU countries should be treated equally or otherwise reciprocal measures should apply. There have been calls within the EU to respond tit for tat and impose EU visas on US citizens, if the issue does not get resolved soon.

So in the dispute above that is being hotly debated, Croatians (for example) want the EU to enforce visa free entry to the US as reciprocation for the visa free entry to the EU. But according to what you say, now US citizens who happen to be of Croatian descent don't have visa free entry to the EU and must get a Croatian passport.

That's how I'm assuming how ETIAS will be implemented: you're usually not eligible for visa-free travel if you're already a citizen. In the past, border police never really cared if you tried to enter EU on your Canadian passport, even if it says you were born in Italy with an obviously Italian name.

But if it's the machine that's deciding these things based on the letter of the law, you might have a problem.

Maybe ETIAS will have a bigger carve-out for these situations than the US and Canada (which exempt eachothers' citizens). Or maybe they won't.

> In the past, border police never really cared if you tried to enter EU on your Canadian passport, even if it says you were born in Italy with an obviously Italian name.

Wouldn't that be an unreliable test, since you could've renounced your citizenship or have been born to Canadian parents visiting Italy, since Italy is jus sanguinis [1]?

[1] https://en.wikipedia.org/wiki/Italian_nationality_law

Correct, but the point was the border police never bothered to inquire. Even the US let’s you renounce your jus soli citizenship.

Now you may have to state Yes/No to a question about other citizenships, when the best answer for a lot of Americans (a nation of immigrants) will be “Don’t know for sure, maybe”.

> Many European countries automatically make people their citizens by lineage, not place of birth.

Automatically?

Source?

The general concept is here: https://en.wikipedia.org/wiki/Jus_sanguinis

Croatia: http://eudo-citizenship.eu/NationalDB/docs/CRO%20Law%20on%20...

Section 4: "A child acquires Croatian citizenship by origin: [various criteria about who your parents are]" There's no "may" or "can".

Germany: https://en.wikipedia.org/wiki/German_nationality_law#Descent...

"A person born of a parent with German citizenship at the time of the child's birth is a German citizen. Place of birth is not a factor in citizenship determination based on parentage."

Italy: https://en.wikipedia.org/wiki/Italian_nationality_law#Attrib...

"Italian citizenship is granted by birth through the paternal line, with no limit on the number of generations, or through the maternal line for individuals born after 1 January 1948."

France: https://en.wikipedia.org/wiki/French_nationality_law#French_...

"French citizenship by birth abroad to at least one French citizen The child (legitimate or natural) is French if at least one parent is French."

Some countries (like France) require the birth to be registered, while others do not.

There are literally tens of millions of Americans that are Italian citizens, from their grandfather or great-grandfather, without knowing it.

There are also cases where a US-born may be eligible for other citizenship but must apply. (Ireland, for example, if either parent was Irish.)