They do this so often that this behaviour is ingrained.
It is conceivable that they may be distracted and fail to complete the action of turning on the white lights, say:
* get a message from Control to look out for vandals throwing stones (Seven Hills). Driver distracted. Fails to turn on white headlights.
* passenger tells Guard about a switch board door being loose in a carriage (Chatswood). Guard bells Driver that he is leaving his compartment to lock that door. Driver distracted.
* Have encountered at least once in a lifetime, seeing RED lights on the front of a train.
Both these examples are very rare, and should they happen, so be it.
The overall conclusion is that the white lights were almost 99.99% on.
Are there any circumstances by which both red and white lights at the ends of a train are switched OFF?
Turning on the White switch, unless there is "Lamp Proving", does not of course mean that the white light is showing if the lamp is broken. Does the Driver have to get out and check, or is there a mirror?
The drunken lady may of course been looking Up the Down line or v.v.