It is good to know what your power source is doing. I have seen many issues in Mexican RV parks that have created damage to RV's.SIMPLE test equipment is all you NEED unless your an electrician don't go into pedestal!
Polarity check and voltage output and your done. Unless you have a voltage corrector which I do and recommend to every RV traveling in Mexico don't hook up if it doesn't check out!
I would say more places in Mexico are not up to standards than are. It would take pages of post to tell all the electrical issues I have encountered and seen in my years of travel in Mexico. That being said it is NOT a reason to skip travel in Mexico.
I have been to big cities in Mexico, visiting family, but our RV travels are to more rural, small town destinations. I can say for sure in my experience contrary to what qtla posted electrical issues abound through out Mexico. But getting better.
Stay thirsty my friends!:C