Henry,
Nearly there, the pumps are ON for flight, just that at some time into the flight the level will reduce and the pumps will detect that they are no longer pumping fuel, THAT is the point at which the pilot 'interferes' with the switches according to the RFM.
Paull,
Wrong pump switch selection happens as they're all the same size, shape, and colour and are 4 tiny switches all in a row in a not very visible location (particularly at night wearing helmet, goggles and perhaps specs, that's why visual verification of the CAD is important, if the CAD fails, then a VEMD display will take over SOME of the functions of the CAD in a reduced and simpler format, though page switching will be required. As some have said, an automatic function really is the answer.