The one time I've noticed that I did steal something, was when I was playing around with improvising on the piano, and I recorded my session, just to see what would come up. Well, right in the middle, there were about two bars that sounded exactly like something from The Nutcracker!
The really strange thing was that it sounded so similar, you could almost hear the orchestral instruments playing it, and it was just me on my pee-ah-noe. Neither of my parents heard it until I pointed it out, and there was a
definite difference between it and the stuff before and after.

Every time I write something, I am scared I've just stolen it from something else...
That is just something we tunesmiths have to put up with, I guess.
There was a thread on copyright in rec.music.makers.songwriting once, and somebody said that if you only take a small part of something else, and not deliberately, and there's different words, and the rest of the song is different, and the part you "took" isn't obviously from something else, that it was ok, and wasn't an infringement of copyright.
I don't know if that is true, but there are only 12 semitones in the musical language, and there's only so much you can do with that, really.

I guess that raises the question of how to decide what is allowable: how much of a piece is obviously from something else, and how much is just 'musical influence'.

Thank goodness chords aren't copyrighted. We'd all be sunk for sure.

(Please forgive my grammar. I just got home from work, and I really should be sleeping...)

hesperis