Unfortunately, cars are not an insurance product, so aren't governed by the same laws.

Having said that, the sales at the dealership I work at, often try to talk people out of purchasing diesel cars due to low mileages, with ISG and DPF's being fitted. But they don't listen, they want 70mpg, and a stop/start system that saves them even more fuel.
Then moan when they get 38mpg when they do their 4 mile round trip to Tescos every week. Then the ISG system stops working because the battery hasn't been charged sufficiently!

(Even had one that was moaning because his ISG stopped working after 3 years, because the battery had reached 75% health - so he proudly told me, "it's okay, I found the problem, the battery needed the electrolyte topping up!" (face-palm)
On an AGM battery - er no! But he was an ex-auto electrician and knew all there was to know! So, who am I to tell him he's wrong!


Anyway, sorry I'm digressing, most of the time, it will say in the vehicle manual what is required to allow DPF regeneration. If the customer fails to follow that guidance, any damage is self-inflicted.


Example: Handbrake fails, car rolls down hill and gets written off, causing several ££££'s of damage also.
If customer didn't follow hand-book guidance, leave vehicle in P or in-gear. Manufacturer not liable!