Gidday LD
Just a thought, what would your insurance company say in the event of a fake hitch failure in the event of an accident?
I couldn't imagine it would be very favourable
Where a purchaser relies on the expert advice of the vendor (which would be a presumption at Law in the case of an engineered object or part of an object), the vendor would be held liable, not the purchaser. Where the immediate vendor could not reasonably be expected to conduct any kind of intermediate inspection of the object, then the liability would shift from the immediate vendor to the manufacturer.
If the immediate vendor had specifically required or selected the object for incorporation (as in the case of a trailer hitch), then they would need to be able to mount a flaming good argument in court as to why they considered that particular object to be "fit for purpose", "reasonably fit for the purpose for which it was sold", and "of merchantable quality" under the various legislative instruments that apply - mainly the under the various Sale of Goods Acts in the various States and Territories, but also various consumer protection laws.
If they could not mount such an argument, they may well be found liable, rather than the manufacturer. This gets very difficult, very quickly. If the manufacturer had not made the object properly, then they would be liable, not the immediate vendor. "Sale by description" and "Sale by sample" are further wrinkles in all this.
At the end of the day, the purchaser could not have an insurance claim of any description rejected on this basis. There is an exception (of course ... ). If the purchaser has modified the object in question, or caused it to be modified, then liability shifts to the purchaser absolutely, and the insurer could possibly void the policy and claim on this basis. It would all come down to the facts of the particular matter.