Even iTunes is guilty of this (on OSX of all places!). Try to edit a songs info and use the normal CMD+Arrow to navigate to Home/End, it will move to the next song. Completely inconsistent and from within Apple on an Apple OS!
As a metadata fascist, this drives me nuts. However, in earlier versions of iTunes (pre-Lion ?), the shortcut was disabled and did neither. I assume they use non-standard text-input.
So it's not exactly the same issue as the Chrome thing: the user assumes this is a text field that implements the standard shortcut, while in reality the text field doesn't answer and the call is redirected to the main iTunes interface.