It's not as unlikely as you'd think. Even in the U.S. we used to routinely have to put in slop factors to account for contractors that would routinely deliver

It's not as unlikely as you'd think. Even in the U.S. we used to routinely have to put in slop factors to account for contractors that would routinely deliver gear in excess of spec. It wasn't until the most recent SSN class that they were able to finally hold the line against the contractors and sub-contractors... but at least the design itself would have weighed what was expected.