2) You are misinterpreting the legal meaning of "based upon" which is what my post discussed.
A song in a movie does not make the movie a derivative work; it simply means the movie is distributing the song. The movie becomes a derivative work if, and only if, the movie is based upon the song, i.e., if some plot or character or some other aspect of the movie draws elements from the song. (For example, any random episode of Glee.) If the song could be replaced with another song without changing the movie, then no part of the movie is based upon the song, and the movie is not a derivative work.
A “covered work” means either the unmodified Program or a
work based on the Program. - GPL
You are right that a movie don't become a derivative work of any preexisting work it includes. Rather, the movie requires to have performance and "sync" rights to such works or they become legally liable for infringement.
So the real question is, do the GPL give performance and sync permission to the movie producer for using the covered work?
This License explicitly affirms your unlimited permission to run the
unmodified Program. The output from running a covered work is covered by this
License only if the output, given its content, constitutes a covered work.
"To “convey” a work means any kind of propagation that enables other parties
to make or receive copies.".
"Conveying under any other circumstances is permitted solely under the conditions
stated below."
So to correct my statement: The GPL can't come into effect since it is not giving any permission to the movie producer in the first place. The movie producer would have to get a separate license or be liable under copyright. You are right however that movies do not become derivative works of the preexisting works they incorporate.
For more details about sync rights: http://www.musiclawupdates.com/?p=2182
Based upon don't mean "central pillar". If a copyrighted song plays in a movie, it would still count. The song do not need to be a "central pillar" of the movie.
The film could however argue that 1), the small amount of code is not copyrightable, or 2) that they have a permission under fair use.
To answer if something is copyrightable, you have to dig quite deep into case law. Simple pure silence for a set period of time has been granted that status. Its a quite difficult argument to make.
fair use is also a difficult one, since it normally looks down on for-profit exploitation. However, they do look if the market for the original work is "harmed" by the infringement, which in this case is obviously not.
Pressed, the film could be sued and might be found infringing. Had it been 10s of a song, I would say 99% certainty that it would be found infringing. 1 page of a program is less tested in court.