yep.....
Buddy owns a trans shop and has a lot of people that ask him to put a wrecking yard trans in, often times so they can just sell the vehicle. His policy is the same as yours in regards to parts. But then it is only covered against leaks. Only thing that is warranted is that it will not leak and it will not fall out of the vehicle. Beyond that, if the trans is bad well you are sol. And he usually will not install a used trans unless he knows you.....