Also, I will have a Thai bank account, so if it does happen I'll just use that. Already checked with my pension, and if necessary they will direct deposit to a foreign bank.
I have a Schwab account. I will give them my Thai address once I move. I will keep the same account and have all my pensions go into it, including my SS. You do not need to maintain a physical US address, and I would worry about them being more likely to cancel you (the bank) once they figure out you don't live there. How? If you go all year withdrawing money in Thailand only and regularly transfer money into a Thai account without spending or withdrawing a cent in the US. Get a Schwab account. You'll be glad you did.