It's about plausible, forseeable siations, not whether it has actually occurred. I've seen some HSE stats quoted of about 400 reported PEN faults per year, so it does happen.
I have a vague recollection of reading about one actual inury or fatality , I think maybe it was Norway, where wet snow could easily be an aggravating factor
Out of interest. I charge the EV indoors, chargepoint located inside garage, does that have different requirements from an outside installation? I only ask as considering the commando ohme vs the type 2 version. Cheers