Zacytowałeś najprawdopodobniej stare regulacje, które faktycznie w dalszym ciągu wyświetlają się w google, aczkolwiek, gdy klikniesz w link to okazuje się, że strona już nie istnieje.
Obecnie wygląda to następująco :
"(...)
You have misread the terms of the Visa Waiver Program. You need an ESTA to enter the US from Mexico. Here's the relevant sections:
"The Visa Waiver Program (VWP) enables nationals of certain countries to travel to the United States for tourism or business (visitor visa purposes) for stays of 90 days or less without obtaining a visa. Not all countries participate in the VWP, and not all travelers from VWP countries are eligible to use the program.
VWP travelers are required to apply for authorization though the Electronic System for Travel Authorization (ESTA),
are screened at their port of entry into the United States, and are enrolled in the Department of Homeland Security’s US-VISIT program."
The air and sea entry part refers only to the requirement to have in your possession a return or onward travel ticket to demonstrate that you will be leaving before the 90 days is up:
"To enter the U.S. on the Visa Waiver Program, travelers must:
Be a citizen of one of the countries listed above, and in possession of a VWP-compliant passport.
Possess the ESTA authorization.
Plan to travel for business, pleasure, or transit.
Stay in the U.S. for 90 days or less.
AND if entering the U.S. by air or sea must be:
Holding a return or onward ticket. If travelling on an electronic ticket, a copy of the itinerary must be carried for presentation to the immigration inspector. Travelers with onward tickets terminating in Mexico, Canada, Bermuda or the Caribbean Islands must be legal residents of these areas...
If entering the U.S. by land from Canada or Mexico, the documentary requirements are the same, except there is no requirement for round-trip tickets and signatory carriers. You must satisfy the inspecting officer that you have funds to support yourself during your stay and to depart the U.S. (...)"
Wynika to wprost z samego przepisu :
"(...) (11) Eligibility determination under the electronic system for travel authorization
Beginning on the date on which the electronic system for travel authorization developed under subsection (h)(3) is fully operational, each alien traveling under the program shall, before applying for admission to the United States, electronically provide to the system biographical information and such other information as the Secretary of Homeland Security shall determine necessary to determine the eligibility of, and whether there exists a law enforcement or security risk in permitting, the alien to travel to the United States. Upon review of such biographical information, the Secretary of Homeland Security shall determine whether the alien is eligible to travel to the United States under the program.(...)"
Ergo - niezależnie od rodzaju przejścia granicznego wypełniamy wniosek ESTA.