"The Carnet guarantees to a foreign government that the vehicle it identifies, having been granted temporary importation status, will be removed from the country within the time limit imposed by the respective jurisdiction or if not, that the country will be paid all duties and taxes that would be required to permanently import the vehicle. Using the Carnet is an alternative to leaving cash security deposits with foreign governments. It allows free movement and unencumbered access between foreign countries. Use of the Carnet is restricted to the countries listed on the back cover. It is valid for one year from date of issue." - Canadian Automobile Association.
Fortunately, no governments in the Americas require a Carnet, so we're off the hook on this expensive piece of paperwork.