Pilgrim, proof reading on PPRuNe appears to be like the old music hall expression: "ladies and gentlemen - mainly yourselves!"
I know with the couple of magazines and other printed matter that I've helped compile/edit, almost invariably some cockup, usually in the plural, slips through, and is the first thing you spot when you open the box from the printers...!
Love to work on an AvMag for the day job...