What proof is needed to reenter the US by land at 96 days on VWP?

Question

Some friends flew into the US (LAX) under the VWP and drove into Tijuana, Mexico. They will be in Mexico for 2 months before flying to El Salvador, Costa Rica, and Colombia for a month and then back to Mexico.

They are booked to fly out from LAX 96 days after first arriving, and will be driving back to Los Angeles from Tijuana on that last day.

Because this is past the 90 days permitted on VWP, and because the further flights were from/to Mexico, what evidence (if any) would be needed to cross at the land border back into the US?

I understand that because they traveled to South America they are within the rules, however the US CBP won't have evidence that they have left the US until day 96 when they try to re-enter.

This is a similar question to Can I acquire a second ESTA a month after the first ended for the purpose of transit? however that Q&A doesn't mention the land borders.

Answer 1

They will need to prove two things: first, that they left Mexico and went to Central/South America when the say they did; and second, that they are not illicitly trying to create a long stay in the USA by combining two or more VWP entries.

For the first thing, they just need to show proof that they were in South America. This could be some combination of used boarding passes, ATM withdrawal receipts, passport stamps (exit from Mexico and/or entry into South American countries), hotel folios, car rental receipts, whatever sort of official or semi-official documentation they can provide that indicates they were really in El Salvador/Costa Rica/Colombia when they said they were.

For the second thing, probably the best they can do is to show their confirmed tickets out of LAX the next day. If they have a reason they need to be in their home country by a certain time (e.g. work or school), evidence of that would be good for the second point as well.

Remember, as always when dealing with immigration officials, answer truthfully anything you are asked, and don't volunteer any information beyond what you are asked. In this case, that means don't show up at the checkpoint and dump your binder of evidence on the officer's lap – just have it on hand in case he or she asks for any of it.