> That's an odd comment, considering most composers are blamed for that very
> issue and aren't looking to the film for the reason behind the use of
> existing themes and passages in a sequel.
But your comment is odd. Why would a composer not be writing the music to what was going on in the film? Isn't that thier job, to enhance and support what is going on visually? In this case, if the Ark appears in a scene, then the composer and the audiance is going to expect to hear the "Ark Theme" just as it appeared in "Last Crusade".
Of course it can happen where music tied strongly to a scene in a previous film is used again, and without any real reason behind it (thinking of "Revenge of the Sith" here). The only thing you can say in that defence is that many times the composer doesn't have the final say on music placement - the director does. You often hear about the composers surprise to find music they wrote for a specific scene not used at all, or moved somewhere else.