That would be one heck of a philosophical debate when does improvisation become unorriginal pasting of licks? Or for classical music when does pastiche and parody (I'm thinking Sullivan's admited use of a "Verdi Feel" in some of the comic operas) become plagiarism.
I am interested in this debate. If I can give a potted history during my music GCSE course I had to "do some composition" with my classical leanings my terror was "Oh **** I've got to write a symphyony" Between the ages of 14 and 16 I struggled and with a few days to go I threw out a ditty based on a Tolkien poem.
I hadn't noticed but I even sang it wrong on the recording and made it sound for about 3 bars like "Puff the Magic Dragon" Upshot I was accused of plagiarism in my exams threatened that all of my results would be voided (With more than half my papers still to sit). I had a near breakdown and took all of the rest of my exams on tranquilisers.
So you can understand how I feel when I watch "Les Mis" and hear "The Humming Chorus" I'm not accusing the composers of any wrong doing but I woud be interested in where the line should be drawn.
(Many Apologisings for hijack of the thread)