I think what Hugo means by "have never done any manufacturing before" is that perhaps they don't realise when a price is too good to be true. There are contract manufacturers who work the way you expect, and who have the forces of contract law ranged against them if they don't. But there's also an underworld, wherein you can get things manufactured much more cheaply if you're prepared to stand over them the whole time keeping them in line. In the underworld they will replace specified components with cheaper ones they had lying around if they think it will still get past board testing -- prototype Trekstor Vibezes came back with a zero-ohm resistor instead of the very-low-value one for current sense. "Experienced" production managers know to watch out for this, in the same way that experienced project managers know who to bribe in tinpot dictatorships.

The unfortunate thing is that the cost difference is so wide, that over time the underworld always wins.

Peter