The news items I saw mentioned that the most obvious way of getting caught was when the border guard saw “born in the USA” on the passport and decided to look up your IRS status. So great-uncle may have been on the hook nowadays, but unless the kids were registered at some time, it probably wouldn’t come up unless they brought it up - i.e. applied for a permit to live in the USA and while processing it they saw “wait a minute, you are already a citizen, but… you are also a felon!”
As I said before, the key issue today is that the recent law change gave all people required to file with the IRS until Aug 31st this year to declare foreign holdings over $100,000 or face a $10,000 fine. This would automatically put a lot of people in violation of US law who actually saved for their retirement or bought a house or farm and paid the mortgage. Do you think any of Great-Uncle’s children meet that criteria? Do they bank with an institution that has ties to the USA (subsidiary or US branches?) If so, Uncle Sam could force the bank to freeze their assets and possibly transfer them to the Washington branch.
At least two of them are most definitely in violation. Their bank would have to know that they had a US-born parent, and as far as I know the only Canadian records to hold that information are the census, which is confidential, and marriage certificates within provincial vital statsitics. So chances are they won’t get caught.
My point was that they ought to have renounced their citizenships when they came of age, but undoubtedly never ever knew it was an option.
Having a US Citizen parent does not automatically make you a US Citizen if you are born outside the United States or Panama.
The only way his children (who were not born in the US) would be citizens would be if he was married to the mother who was also a US citizen and one of them had a residence in the United States prior to the birth.
The rules for acquiring citizenship for births outside of the United States are quite complicated. Here is a summary from the US State Department.
Here is the actual law if you want to go into more detail: 8USC1401.
Well I think he was/is. What I think happened is that he turned up for his interview expecting to be told what sort of proofs he should produce only to be immediately pronounced illegal for not having any of it with him. The case got a lot of publicity at the time because of the large amount of stupid involved.