Yes, I figured that. But the quote and the song lyrics are close enough for them to be easily confused.
I have a copy of Pygmalion, so I knew where the quote was from, but I doubt most people would right offhand.
Or, as suggested above, it was corrected when that episode was edited for broadcast. Either way, I was surprised when they revealed the mistake, since I hadn’t noticed anything.
I think it’s more likely they would recognize the lyrics from the movie, rather than a quote from the play’s preface.
No, but many (probably most) Final Jeopardy questions do not demand that you know offhand, but enable you to put the pieces together, from general knowledge. If you know something about Shaw (granted, many people don’t, but then it wouldn’t do for everybody to be right every time), you know that he liked to write lengthy prefaces to his plays, and that is unusual. Few, though, who didn’t have to act in “My Fair Lady” are likely to have read it as a play.
I didn’t know that about Shaw, but I did remember the lyric that terentii quoted from My Fair Lady. Figuring that Professor Higgins was probably a similar character in the play and the musical, and that Alan Jay Lerner may have taken some lyrical inspiration from the play’s preface, I guessed Pygmalion. I wasn’t certain until one of the contestants got it right.
Absolutely correct. The key words “From its preface” both provide a major clue and remove any possible ambiguity.
There was never any question in my mind that they meant “Pygmalion” and not “My Fair Lady.”
Of course, I knew the quote they used, so there wasn’t much deduction involved. 
How do you know the text of the musical doesn’t have a preface? :dubious:
Musicals don’t have prefaces; they have overtures. 