Yes the banks are asking for long term visas such as an O or a B. That is why people use agents to open an account when they are not on these visas. The visa type you opened the account with is saved. If you change visa type the only way a bank would know is if you went and updated them. There is no link with the Immigration system. Just as currently the immigration system is not linked to the tax system etc
Well I suppose DTV holders will just have to take those risks for convenience then. The sky might fall in too but bedwetting about what might happen does not help anyone. PS: When your visa type changes it is not updated at the bank. It is the visa it was opened with.