I allow drow to access archetypes and favored class options from the half-elf list because, being human (race) but having elvish (subtype) traits, I think that it is logical to assume that they have the same potential. I do not, however, let them access that of the elves unless it serves a purpose. One of my players, for example, chose the elf-raised racial subtype that was available to half-elves while playing a drow. I allowed it because his backstory revolves around his adoptive family (of elves) basically hating him in a very Hunchback of Notre Dame inspired fashion. I felt that since it serviced the story and had little to do with monopolizing on racial abilities to create an unbalanced character, I figured I would allow it. The only thing I recommend is that you are aware of the character they are building so that they aren't just trying to pull a fast one on you.