Is when Film and TV directors use the instumental versions of songs (for mood), when the lyrics are the most important part of the song.
A classic example is in the Matrix 2: The first agent fighting scene, the background music is by Rob Dougan. It called Furious Angels and is about the anger you go through when you split up from your love in acrimonious circumstances. If you get chance have a listen to it, as it's clear that some woman has seriously made a mess of his head at some point.
The reason that this sprang to mind was because I managed to catch CSI last night and they use another one of his songs for their theme music (bandwagon anyone), as an instrumental. Again the lyrics for the song are the important part - if I remember right this is about someone whose lover shoots them in the head and leaves them for dead (A good song for Kill Bill perhaps).
Now obviously I don't begrudge the artist their royalties and all that, but I'm sure it must be slightly annoying to them as well after pouring so much emotion into the song......