Preliminary research indicates there are banks that treat bicyclists at drive-through with the same deference they do motorized customers. And there's at least one bank which isn't sure of it's policy. That's probably why I didn't spend the time on it back when. So look to this spot every so often and see if I've gotten in gear.
Customers are customers.
Insurance and Safety. The insurance issue is often thrown out as a red herring. Perhaps you're the first bicyclist who's ever used the drive-through facility. A bit of John Forester here should clear that up. Bicyclists fare best when they act and are treated as drivers of vehicles.