Just read the report on that 737 making an emergency landing at KCRW due to a holein the fuselage.
Hornet, do you have a link to the report?
I wouldn't be surprised if subtle crown area damage on a fuselage was caused by the maintenance troops walking around up there with their tool boxes and size 14 brogans. Putting a slight dent in the skin next to a frame might set up a localized stress area which 10 years down the road would vary from the engineering fatigue expectations. With all that terrain up there it would be a bear to inspect. This scenario doesn't apply to just B type aircaft either. Let's hope that the guys with the sliderules worked out the blowout limitation strategy properly as they seem to have in this case.