Years ago with the Chief pilot checking one of the old crusty captains:
On the walk around, "What is that antenna for?",
"Don't know mate"..
"Well, what does that vent do?"
"No idea"
"OK, tell me what that marking signifies?"
"Not the foggiest idea sport"
Very put out now, "Well I hope you don't mind me asking you these questions??!!"
"Not at all Noel, if you don't ask questions you'll never learn"