It will depend on whether we're talking about existing accounts or new accounts. With respect to existing accounts, it's much along the lines, at the general level, that you describe. An electronic search is generally the procedure. If the electronic search shows up a U.S. indicator, then that could be the prompt for further inquiry. That's all that's required. There's no other sort of investigation involved, except with high-value accounts.
For new accounts, it will be open to the banks to see, on the basis of the documentation they receive, whether there are U.S. indicators. It may also be the case that a bank would wish to put the question to new account holders, to ask the question explicitly.