Tom, your idea that its merely the Mexican Government playing a bit of one- up-man-ship seems to have a factual base. From this link http://tinyurl.com/29xrr I have copied the following:

"Relations with Britain are already sensitive because of allegations Britain helped the United States spy on Mexico's U.N. mission in the run-up to the Iraq war"

I would have thought any ideas on mining would quickly be forgotten when you take a look at their weather. About 4000mm of rain a year! Take a look http://tinyurl.com/3gjrw
(On the survival/adventure theme, the "expedition reports" make good reading.)
As you said we live in wacky times.
Martin