This is pretty simple, no need to worry about whats right or who did what.
When any tool breaks, its either a defect in the tool, or operator error.
Maybe you got a rare bad pair of pliers.
Maybe Knipex quality *** has gone down the toilet.
Maybe the pliers were used improperly.
Without examining the pliers that's all we know. Seems to me all three areas have been speculated on fairly. I've seen too many needle nose pliers with broken tips in junk tool bins not to suspect that one jaw was slipped into the eye and the pliers were bent over something to pry the pin out.
Am I the only one here with more than one set of specialty pliers that I would thump somebodies head if I caught them using them like a regular set of pliers?
*** Knipex Quality
http://www.knipex.com/en/the-company/knipex-the-company/the-pliers-specialists/
We concentrate our knowledge and expertise on pliers. This is the only way to justify our claim we are the best supplier in terms of quality, innovation and efficiency.
Our success is assured by 800 qualified employees and we attach the greatest importance to their basic and advanced training.