"Tom Sawyer: All I've got in my mind at the moment [is] a picture of a number of Engineers reading this thread, rolling their eyes at some of the comments of non-Engineers about how perfect they would be at doing our job and they would never make this mistake, or have the solution."
Agreed, (am not a 787 pilot), but I don't think we are claiming that we never make mistakes, (I've made some howlers).
It just seems rather foolhardy of the manufacturer and operator that; knowing about the problem, an indication of some sort was not applied to all the aircraft until the wrong hole could be blocked off by the official mod. Or a photo and a warning printed in the engineer's notes for this procedure. Or even simply a photo emailed to all engineers. Do engineers receive an equivalent to our NOTAMS and Ops notices?