When is it a good thing to have a knot fail while fishing?

Never you say?
Read on..

While fishing up at East Cape one night during the last QB weekend, out of the darkness we heard the unmistakable sound of a rod stand being dragged along the shingle beach.

Headlamps on, and looking towards the sound we were greeted with the sight of Michelle's rod clattering across the stones towards the water.
We both took off in a good attempt to break the world 50m sprint record, and I managed to get a hand on the rod butt just as it was entering the tide. The line was slack, whatever had taken it was gone.
Winding in the slack line revealed that the shock-leader knot attaching the bottom snaplock had come undone..

Michelle had forgotten to back off her drag after casting, something had grabbed the bait and pulled over the rod stand.
Had the knot held we would not have that rod and reel anymore...