an elf who merely passes within 5 feet of a secret or concealed door is entitled to a Search check to notice it as if she were actively looking for it.
Agreed - that's the ability, so a Search roll is made whenever the elf passes within 5' of a secret door, whether or not he is looking for secret doors. Maintaining a record of the Elf's search modifier (and any other modifier that will routinely be used for secret checks of which the character is unaware) isn't that tough.