I agree that the documentation should be used and not necessarily the silk screen. The silk screens can be a first line of defense, but nothing beats the proper documentation.
Years ago I visited a contract manufacturer that a friend was working at and he told me about this situation. It was a large facility with many, many, production lines. They were building the same board on two of their lines.
The QA person on each line noticed that the silk screen showed that there was a cap and resitor (next to each other) that were swapped in placements. The silk screen showed that the cap was placed where the resitor should be and the resitor was placed where the cap was suppose to be placed.
One QA person checked the documentation and was informed that the silk screen was wrong and the placements were actually valid. The QA person for the other line simply told the operators to change the program for his line to match the silk screen.
Now since the silk screen was wrong they were building 50% bad boards for many weeks. Oddly enough the boards would pass the functional tests, so all the boards were being sent to the customer. But once the completed assembly was installed in the field they started getting many failures and the customer was quite upset that so many bad boards were made from a QA person that didn't do his job properly.
That QA person that told the operators to change the program was quickly looking for another job.
Lesson: Don't trust silk screens.
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