Originally Posted by
Steve_Hun
Does the CBP get your info from the airlines when leaving the country, or in reality they just don't really care about enforcing the 90 days rule? Not that I'd plan to overstay, this is just purely out of interest.
They do, and they do follow up.
That's what the small green slip was for that they stapled in your passport. The airline took it at check-in or upon boarding and sent it to CBS to indicate you left the country. Now it's all computerized but it's still the airline who is in charge of submitting the info.
Of course, this doesn't always work. So there are stories about people who are put in a holding cell upon their arrival in the US and then sent back home on the next plane, all because they "overstayed" even if they didn't. Happened to a Finnish girl some years ago and it was all over the yellow press here. According to the story, they didn't even tell her what was wrong so she couldn't try to prove that she didn't overstay on her previous trip.