Lock-Ring pliers, why is there a notch on one side of the tip

[johnnyclack]

I am not asking about snap-ring pliers, my question specifically pertains to Lock-ring pliers that are of the type used on external lock-rings that would be in place on the end of a splined shaft.

The tips are knurled, and while one side is a flat jaw the opposite is notched. I have always wondered how the notch is to be used. I just picked up a new pair tonight and so once again the question is in my mind.

Any answers or wild a** guesses out there ?

thanks
js