That seems like a basic consumer protection issue that's mostly already solved in the developed world. When I get my car serviced, it's understood that I will hold the mechanic responsible for everything so they don't even bother trying to put sketchy parts in my car.

yet Prius catalytic convertors are apparently a big market, so much so that it is a regularly stolen item. so someone is buying these parts to install when a car is serviced.

[1] https://www.inquirer.com/business/toyota-prius-catalytic-con...

[2] https://www.msn.com/en-us/autos/news/thieves-target-toyota-p...!

[3] https://www.theguardian.com/money/2020/feb/01/catalytic-conv...

> The thieves make about £300 to £500 from every converter stolen, fenced through scrap metal dealers, with car manufacturers warning that a gap in the Scrap Metal Dealers Act 2013 enables dodgy dealers to buy them without checks required on where they came from.

Catalytic converters are filled with valuable metals (platinum, palladium, among others). They're torn apart and the expensive metals are resold. The cat isn't being put on other peoples cars.

They're not making money by installing the converters into Priuses.

They are making money by selling the platinum inside.