I'm just thinking from a viewpoint of how much work it is is to fully assemble the engine, put on new filters, fill with expensive break-in oil, juggle the engine into the engine compartment, struggle with putting the exhaust system and cooling system together with fresh coolant etc.. just to have an issue that could have been found and rectified very easily with the engine on a stand, especially with clear evidence that proper assembly protocols were not followed from the start.