meaning that in a self regulating industry it is almost impossible for a single action to cause an accident
Absolute rubbish. A pilot fails to flare and hits hard, jerks back on the control column, and gets a tail strike caused by a combination of thrust still applied, spoiler actuation on impact and hard back stick. The pilot may have done perfectly serviceable landings previously, but on this occasion he didn't. So how the hell can the regulator, airline management, ATC who asked him to keep up speed on final approach, the rostering staff and Uncle Tom Cobbly and All, be blamed for a error of judgement by the pilot. The verdict must be pilot error.