SoCal
That NYT article states
Last year alone, 2.9 million foreign visitors on temporary visas like Mr. Smadi’s checked in to the country but never officially checked out,
immigration officials said. While officials say they have no way to confirm it, they suspect that several hundred thousand of them overstayed their visas.
This doesn't mean a great deal unfortunately, because countless millions of tourists enter the USA every year, filling in those cards, but it is (or used to be until very recently) up to the
airline to collect the cards from people leaving, and usually the airline can't be bothered, and neither can be the tourist.
So I reckon half the world must be sitting on the USCIS computer and showing as still somewhere in the USA. I may well still be there myself
USCIS is in a very bad state, full of semi illiterate (but often aggressive, and always armed) ex McDonalds type workers. I got pulled up a couple of years ago, on a brief business trip, because I had an expired M1 visa in my passport, and the name of the school on it showed up on their computer as me not having finished my flight training. Actually I never even went to that school (a bunch of illiterates in Arizona) because they refused to communicate with me and would only talk with the UK instructor who was their agent here, and the M1 was sent to him, but he was abroad, so it was lost. I had to re-do the whole process again with another SEVIS P-141 school, also in AZ... anyway, I got a very unpleasant interrogation in a room full of utterly miserable African immigrants, and when I finally bumped into a person who looked like he had more than 2 braincells and told him they can easily verify my
completed training using faa.gov, he said USCIS has no means of accessing the internet
The 3hr delay nearly caused me to miss the connecting flight but I was lucky as it was a lot later.
In the meantime, their "work to rule" (1 stand manned for a huge # of arrivals) meant that practically everybody arriving that day missed their connecting flights too. Did Immigration care? No, they couldn't give a t*ss.
And this isn't my only, or least unpleasant, experience of US Immigration.
The rest of America is perfectly nice and friendly
So, is it any wonder that no two people get the same answer from these IQ=20 morons?
Personally, I would suggest getting the visa and TSA both done for any training in the USA - except where clearly exempted and in that case I would get neither and say nothing whatsoever to USCIS.