Нашёл-таки официальную информацию: http://portal.sre.gob.mx/was_eng/index.php?option=displaypage&Itemid=55&op=page&SubMenu=
Permanent legal residents of the US and Canada
All legal permanent residents of Canada and the United Sates, regardless of their nationality, if in possession of a so-called green card (now they are pink), or its Canadian equivalent, do not have to go through the process of applying to Mexico City for their entry permit nor do they need the stamp on their passports. They can be issued the tourist card on board the aircraft or at the port of entry to be able to travel to Mexico as tourists, in transit, or for short business trips.
THEY MUST CARRY WITH THEM THEIR VALID PASSPORT AND THEIR GREEN OR PINK PERMANENT RESIDENT CARD ISSUED BY THE U.S.A. GOVERNMENT OR THE CANADIAN EQUIVALENT.
