The USA and Canada now exchange data at the land border. Enter one and the other side will know you exited. However, you can still go through the turnstile to Mexico without a record (maybe until they have a need to dig out some tapes).

Don't overcomplicate things. There are very specific instructions on the CBP I-94 website for what to do if you believe that CBP has incorrect or missing information. The starting point is a phone call although you may pursue one of the written options. Asking BA or writing to the Embassy are the wrong places. As today is a US holiday, you can expect tomorrow to be busy, but I would just make the call, place the phone on mute/speaker & multitask while you progress through the wait:

1. You can contact the CBP Traveler Communications Center at (202) 325-5120.
2. You can formally write to the Department of Homeland Security's Travel Redress Inquiry Program (DHS TRIP). DHS TRIP is a single point of contact for individuals who have inquiries or seek resolution regarding difficulties they experienced during their travel screening at transportation hubs, like airports and train stations, or crossing U.S. borders, including: denied or delayed airline boarding, denied or delayed entry into and exit from the United States at a port of entry or border checkpoint continuously referred to additional (secondary) screening.

You can contact DHS Traveler Redress Inquiry Program (DHS TRIP) at http://www.dhs.gov/trip.

Or, by mail at the following address:

DHS Traveler Redress Inquiry Program (TRIP)

601 South 12th Street, TSA-901

Arlington, VA 22202

I had a quick wriggle around in there, from where I am here in rural Haute Savoie (France). Everything seems to be in order with my last entry in 2017. Probably will get a bunch of men in black coming round here at three o'clock in the morning!

Which is why frequent flyer miles posting and evidence of a card transaction outside the USA will help to evidence you leave when you did.

My girlfriend's records are a comical mess and include her having entered the United States via an air force base that closed in 1992 and has no commercial flights.

After I got approved for my Nexus card and started using it, my records from the I-94 website completely disappeared. so yeah the system seems to be a mess.

Never had any issues crossing the border though.

Perhaps Dublin would be an easier option short of returning to the US since they have CBP and a pre-clearance facility there. Obviously best to sort it out w/o extra travel of course.

There should be no need of traveling to DUB, the US, visiting the Embassy or anywhere. The specific instructions from CBP provide the means to fix this and it will be very surprising if that does no happen with a quick (or not so quick on the day after a holiday) phone call.

The website doesn’t list airport codes - it’s CBP’s reference that port. I assume you are referring to seeing VCV - that’s not Victorville airport, that’s Vancouver Canada airport.

I'm guessing this is also the Southern California Logistics Airport (formerly George AFB) that Moscowflyer refers to, which is perhaps more familiar to FT'ers as Victorville (VCV), home of the desert boneyard where many a retired commercial jet has gone to die (also serving as a parking lot for grounded 737 MAX).

VCV is a 'foreign trade zone' apparently, which can, if I understand correctly, be used as a (virtual) port of entry for goods and freight which affords certain tax and import/export tariff advantages to US businesses. Thus if the flight included qualifying goods the i94 record for each passenger might record VCV as the first Port of Entry in order to register the tariff advantages for the owners of the cargo onboard even though the actual flight never goes anywhere near the place and nobody ever gets off there.

Mind, this is all speculative but it might explain the 'ghost' journeys in peoples records?

Perhaps this is more likely, presuming all those with VCV in their i94 history have actually pre-cleared US CBP in Vancouver.

I know that the US sees a lot of (often imaginary) benefit in being completely out of step with the rest of the world on standards etc. but not to use the standard IATA or ICAO codes for something that by definition is 'international' (i.e. cross-border entry and exit) seems perverse in the extreme! :D

Exactly this.

I have done this about a dozen times in the last two years, and the first time coming back int the US from Canada at Lewiston the CBP officer was completely confused when I explained I had landed in New York three days earlier, but that GE doesn't include any interaction with anybody. Had a nice chat with the folks inside and was on my way about ten minutes later.

My solution to this is to take a photo of the GE receipt to show at the land crossing, along with a quick explanation. Has worked all other times except once, when I again had the pleasure of a two minute chat indoors.

A partial postscript. After a bit of a wait on the phone I spoke to a very helpful lady. She directed me to https://help.cbp.gov/s/questions.

Select Traveller Compliance I-94 and 10 day notification email from the drop down, and you have the opportunity to send a detailed explanation and to upload docs.

A request to BA for the manifest resulted in a pro-forma saying that could take up to 28 days. So for now I have submitted my passport (although as I have not left the UK since returning from NY, that will be of limited use), my e-boarding pass from my phone, and a credit card statement showing spend in NY over the days I was there and then solid retail spend in London. Plus I have offered to submit the manifest if and when I get it.

Now it's a case of wait and see.

I believe the record specifically said "George AFB" I will see if I can find it, she printed it at the time.

Suspect this will be sufficient.

Don't forget that CBP has the manifest directly from BA and can check that directly rather than having you ask BA to supply it you and then having you submit it to CBP.