Here is what MW had to say back in 2004:
First of all keep in mind that the owners of most gasolineras complain bitterly that Petroleos Mexicanos does not pay enough to the franchisee so that a little finagling is to be expected.
In 1994 I spent a considerable amount of time testing 224 pumps throughout Mexico using a NIST calibrated Seraphin 19 liter test measure. The results were written up in an article by Paul Carroll then Bureau Chief of The Wall Street Journal in Mexico City. Mr. Carroll and I tested a pump at the station located at the corner of Reforma and Insurgentes. When Carlos Salinas de Gotari read Carroll's article in the NAFTA edition of the WSJ he popped a cork. The end result after a most definitive expose was and is..............everything remains the same.
You might want to save your breath about "Inaccurate Pumps".
