To use your Holden analogy, I am not a mechanic. But if I buy a Commodore and it needs work, I then take it to a bloke who has been trained by Holden in their vehicles. IF he makes a mistake that disables the brakes under certain conditions and kills my missus & kids, why should he not be liable for it? IT isn't that old mate misused the seat, but even if he had to use it in anger, it would have been rendered useless, as shown in the following paragraph...MB knew there was a risk of the pilot's parachute failing to deploy if a particular nut & bolt combination were too tight, and they knew this 20 years ago, but apparently failed to warn the RAF, so not only did the seat malfunction (with the safety pin being described as "effectively useless" by the Coroner), but, having been inadvertently ejected, a survivable accident was rendered a fatal one by the failure of a piece of equipment that MB knew could be defective.