....I think what MEX is inferring is: don't count too much on the Mexican OnStar service, because the cell coverage is not nearly as stated in the GIS map mash-up screen-shot (taken by Gtla). Additionally, how reliable would a Mexico-based OnStar "towing service" call actually be at any randomly-driven stretch of road in Mexico (ie. when a foreign RV visitor is driving off the toll roads), will his/her OnStar MX link (and the service call reception to destination time frame) be reliable and apropos for the emergency situation ?
BTW: there are large parts of South America covered by OnStar currently.
IF OnStar becomes available to US and Canadian GM owners for real in Mexico, perhaps planning for the worst and hoping for the best would be prudent...