For once, again, I need to concur with Regulateur ;) Things are more complicated today. But I would add that IWC is dead serious about absolute quality control, as I described in several articles here including
www.iwc.com/forum/en/discussion/58188/
and also
www.iwc.com/forum/en/discussion/49990/
I will say that a large number of people in the factory --more than a handful--work exclusively in quality control and each step of the production process has someone assigned to check.
The two most recent incidents really are blown out of production. The dial with the wrong numbers was a huge goof, done by a supplier, and which no one admittedly caught --including the dealer and the purchaser! I probably would have missed such an incongruous error too. It is a real goof but statistically an .001% error.
The strap is another matter. Watches leave the factory without straps attached, and they are put on in the country when the watch arrives. I can't tell if the strap was defective (again by an outside supplier) or was mishandled when fitted or by the dealer or by the customer. It is an easy fix.
I am not excusing any such errors nor saying that IWC cannot do better. But if each watch has an average of 250 or 300 precision parts, and goes through dozens of factory processes and then hands in distribution, there will be some errors which, statistically are small. I have encountered problems with Patek, Breguet, Audemars, etc. --all of which can do better, but some of it is the nature of hand-produced complicated miniature machines.
Statistically, and compared to many other brands, IWC devotes more resources to, and gets better results regarding, quality control.