Ron, what is the "nightmare" you are talking about in stopping the direct deposit? I have my US Social Security DD'd to BKK bank for a fee of 0.25% and then it costs me nothing to withdraw (as long as I'm in the same province). I have had Direct Deposits with both from my former employer and with Social Security and never had a problem switching banks. Usually the switch is made within a month's time.
As far as the Thai bank "getting your income", some bank is going to "get" it, unless you are putting it under your mattress.
By the way, if your are talking Social Security payments, they will not send those payments to you if you are in Cambodia or Vietnam. Some exceptions can be made in which case you have to appear at the American embassy to pick up your money "if you qualify" and I don't know what it takes to qualify.
The following is taken from the SSA Publication 05-10137:
"Social Security restrictions prohibit sending payments to individuals in Cambodia, Vietnam or areas that were in the former Soviet Union (other than Armenia, Estonia, Latvia, Lithuania and Russia). Generally, you cannot receive payments while you are in one of these countries, and we cannot send your payments to anyone for you. However, exceptions can be made for certain eligible beneficiaries in countries other than Cuba or North Korea.
To qualify for an exception, you must agree to the conditions of payment. One of the conditions is that you must appear in person at the U.S. Embassy each month to receive your benefits. Contact your nearest U. S. Social Security office or U.S. Embassy or consulate for additional information about these conditions and whether you might qualify for an exception.
If you do not qualify for payment under this procedure and you move from one of these countries to another country where we can send payments, you can receive all the benefits for which you were eligible except when you were in one of the countries listed in the section Social Security restrictions."
http://www.ssa.gov/pubs/10137.html#additional