Ash: For now, since there is not a simple way to establish a particular relationship in "relatiioinships on the stone", I have chosen not to use the "relationships" features very much. There is just too much ambiguity, in my opinion. Even if the stone clearly says "Annie" wife of the above John Lennon", there is not a place to clearly express that in the "relationships on the stone" functions. I have noticed that some others have chosen just to transcribe the entire set of stone inscriptions into the field marked "Grave Description". I suspect that BG is trying to resolve this relationships function, at least I hope so. It would be very nice to have drop-down menu that gives us the option to add a definite relationship.
If the "relationships added by users" was a lot more convenient I might be using it more often, but now I am just using it for rather complicated family plot situations, where you might have a father an adult daughter buried in a dual plot, and it looks like a husband/wife but is not. And I only do that when I have found the correct information in alternate sources like the genealogy sites and other grave indexes.
I hope that someone from BG will reply to you with some response that this will become more usable with better data integrity, along with some posted guidelines on how they expecttus to use these functions where the functionality is not pretty obvious.