I am a Mexican that has worked in the financial industry and I believe there are several misundestandings regarding how financial institutions work in Mexico.
First of all... Lets talk about the bankers preparation.
99% of Bankers in MExico are University graduates. Even though, in the diverse activities that they provide to customers they are required to have (or not to have) some certifications from The Mexican Asociation of Bourse Institutions (AMIB http://www.amib.com.mx/). An AMIB certification allows a banker to provide investment advice to customers,. So yes, they are prepared at a minimal standard. Perhaps the "Issue"in Mexico, is that many institutions does not have clear controls regarding the match that must exist between the investors profile and what is being advised on their account.
It is extremely important to understand what is being offered to you as an investment. Being CETE the only instrument that is almost risk free as it is government backed. Usually, a retired expat should expect to have a major part of its portfolio in CETEs and some of your money in other investment funds.
Now lets talk about the bank guarantees.
Bankers can lose their AMIB certification and go to jail if they incur in major wrongdoings. Also, deposits are guaranteed in case the bank fails (please note the Only if the bank fails) up to 2.5 million pesos aprox. Therefore, The only guarantee you have from an investment loss is to consider which kind of instrument you are investing and the quality of such investment. Therefore, Never Ever, under any circumstance give a Mexican Banker a Power of Attorney to manage your investments at will. This figure is called a "contrato discrecional" in Mexico. If you do not sign this, you will be required to sign a paper, or provide a telephone recorded instruction for any investment you make in your account.
How to solve customer complaints to banks in MExico:
Last, but not least. In the US and CA, any allegations by customers are usually solved by the bank before going to the Consumer Financial Protection Bureau ( or equivalent in CA). Here In Mexico, things work out a little bit different. If you complain to your bank, there is a very little rate of success, but if you go to CONDUSEF ( The mexican financial consumer agency), you have a great chance of "winning the issue against the bank". Therefore, if your account is drained by a bank executive, or you do not recognize any transactions, you should go to the bank, ( & expect a denial of your claim) and afterwards, go to CONDUSEF, where your issue will probably get solved.
Regarding Monex, I assume that most of the damage was made by a banker making fraud by falsifying customers signatures, with such executive providing instructions to drain the accounts. Thats the reason why Monex is willing to settle the claims. IF the trouble had arised from bad investment decisions, Monex wouldn´t be offering to settle to customers as it is a common practice to open Discretionary investment accounts to expats in MExico.
I hope this helps you guys to understand how things work in MExico. IF you have any other questions, I will be happy to give some more insights.