by Brian Crow:
If the customer does not provide an updated W8-BEN, then the bank is required to start back-up withholding for any interest payments to the account.
by Ken Golliher:
It's the customer's responsibility to make certain you have a "current' W8-BEN, not the bank's responsibility to get one. As indicated, your sole compliance responsibility is to impose backup withholding when it expires. That's not a big deal. If you send a letter 30 days prior to expiration telling the customer what you need and when you need it, you been more than just compliant, you have been courteous.
I have never understood why banks put in elaborate follow-up mechanisms for expiring W8-BENs. The compliance responsibilities for interest bearing accounts held by non resident aliens are burdensome enough as they are without attempting to hold hands.