I apologize to Dopers tired of this question, but placing the truth on record is a fetish of mine. 
I’m glad you’ve put me on Ignore, Sam, so I can finally correct this without you re-posting this mistake yet again.
All that a foreigner needs to open a bank account in Thailand is a non-I visa. I know about a dozen foreigners who’ve done so and only one (you) who’s been asked for a work permit. Why you are asked for the work permit I don’t know. My best guess is a conversation like
Sam, opening my account: “Would you like to see my work permit?”
Bank officer: “Uhh, OK. Why not?”
That your claim is absurd is logically clear as I explained earlier: Most people with retirement visas open bank accounts at least two months before they apply for the retirement visa, to satisfy the “financial proof” requirement for the visa, and retirees are not permitted to have work permits. (I notice you’ve added “retirement” to your claim but the retiree is never asked to return to the bank to validate his account!)
All that a foreigner needs to open a bank account in Thailand is a non-I visa. One foreigner (Sam) was, supposedly asked for his work permit. I wish he would say “I had to show my permit” rather than the false statement “permits are ‘technically’ or ‘generally’ required.”