To sue anyone for something that they didn't do. For instance Salting the Roads to prevent Ice Buildup which is the biggest cause of Rust in Motor Vehicles in the Northern Hemisphere.
It is just as easily argued by the Lawyers for the Car Maker that the owner knows of this and has failed to take the necessary steps like having their car Rust Proofed which is an option so they accept the damage.
Of course if like Porsche they Hot Dipped Galvanized their chassis after the bare Structure was welded together the costs would be greater and fewer people able to buy that model.
Though if they put in a Design Fault like the Go Peddle not working and causing the car to go as fast as it can, or a fire to start because a bit of plastic has collected flammable fluids and allowed them to ignite then the car maker does get sued.
What we are talking about here is deliberately not using a Known Fault after it has been discovered which is different to deliberately designing in problems and not taking any steps to prevent them from being there to begin with.
Sorry but after working in the Auto Industry as a Designer I can honestly say that they do not deliberately use faulty designs, that doesn't mean that things are not faulty just they they don't know that they are when they are specified. There is a very big difference between being sloppy and not caring and not knowing of an issue.
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