Nothing made by man is perfect. A friend of mine seized an engine on his new Rolls-Royce, because of swarf left in the oilways. That was around 25-30 years ago.
The very first new Leica lens I ever bought -- a 35/1.4 pre-aspheric, that I still own -- had a focusing mount that jammed out of the box.
I called the dealer. He said, "For extra speed, contact Leica direct."
A languid young man replied, "Oh, yes, it will take two to three weeks to repair."
I replied, "No it f***ing won't, it'll take return of post to replace."
He said, "There's no need to be like that, sir."
I replied, "Clearly, there is."
It was replaced by return of post, after the dealer heard that story.
That was over 25 years ago, too. This sort of thing would not happen nowadays, not in the UK, not in Germany, nowhere I know. If anyone is still berhaving like this in the US -- and it's normally just one person, or a genuine lost letter or e-mail, which is why I prefer the 'phone -- then I suspect Dr. Kaufmann may have Words with them.
Cheers,
Roger