Successive products associated with targets to be electro-optically read are swiped, in their respective turns, past a window in a point-of-transaction workstation. A motion detector detects movement of each product. A reader electro-optically reads a target associated with each moving product. If the target associated with each moving product has not been read, then this event is deemed suspicious, and the event is flagged for a security investigation designed to deter product theft by sweethearting.