Hi, I am from Mexico and I have traded several times without problem, however the service is slow and I recomend 100% registered mail. Some people at the post office like to steal envelopes, so if the mail is registered you will not have those problems.
Yes he says everything must go register with insurance in case lost his family lives in Durango so I'm not sure from where you send to but to some places may be worse than others and it might also depend on where you're shipping from. Also a lot of people in the U.S. send money back there to their families and that may be one of the reasons why.
I've noticed turbinux does have good feedback with few people I've swapped with before, so maybe his post is reliable, but I'd definitely check the town I was sending to and not send to some dinky village in the middle of the desert; but I'm sure some of the larger cities may be a lot more in order and I would feel safer sending to those.
Mail cert.. but have issue with Mexico city to big great city nice people I been to Mexico a lot
went I was in Arizona a friend of mine would have me go with him to a family ranch in very southern Mexico
oh god could his mom and grandma cook. Some of the nicest people on earth if you get way from the mess.