hi,
WD40 is a water repellent and NOT a lubricant - the clue is in the name WD = water displacement !!!!!!
Trouble is Gary, it says the following on the can:
Stops Squeaks
Loosens Rusted Parts
Frees Sticky Mechanisms
Loosens Rusted Parts
Frees Sticky Mechanisms
And in other walks of life like DIY, car and motorcycle maintenance etc etc it is quite effective.
You can see why people are tempted to use it.
But your advice about not using it on binoculars is certainly to be heeded.
Lee