So do I assume that the CEC also didn't officially allow black/white loomex to be used as a switch drop, even if it was used in practice?
Over here, black is reserved for the neutral, but the regs. allow it to be used as a hot wire if it is suitably tagged at each end. For example, our standard 2-w plus gnd cable is red & black, so on a switch drop we normally use red as the feed and black, taped red, as the line to the light.