The roots of the word currency do not stem from your sense of "current", by which you seems to mean something like "immediate". It primarily comes from the Lat

The roots of the word currency do not stem from your sense of "current", by which you seems to mean something like "immediate". It primarily comes from the Latin currens which means to run, or flow. It's monetary sense comes from that, as money can be thought of as flowing throughout the economic system. The temporal sense of "current" comes into play only as denoting something like "the present day medium of exchange" not "immediate". Bank notes and checks for example are both forms of currency but are not immediate. The immediacy of cash-- separate from its status as a currency-- does not confer it special rights. To use something less trivial than a bagel, think of a car. If the dealership is notified that it received stolen cash for a car, it now knows that it is in possession of stolen money. It cannot legally keep money it knows was stolen. The exchange it entered into with the thief was itself not a legal transaction. The cash goes back to the rightful owner, the dealership gets to fight it out with their insurance company to get its own money back.