Yes Patek Phillipe has an ongoing commitment to produce watches of a very high level of quality!
Planes are produced to a high level of quality, still there are planes crashing!
Yes the Seal implies reliability, but is not a promise of perfection, just of maximum work towards perfection.
Regarding complaining you're right the best service doesn't need complaining, maybe I badly choose my word, but still when you have a reliability problem you have to let Patek Philippe know in a way or another, whatever word you choose. J
Cheers
Dje