'Linked' data points in separate places - what if one is missing?

[Grunners]

There are a number of data points in the editor that presumably are linked, yet one can exist without the other. E.g. I could add a new current contract to a free agent player, but not add the same club to his playing history tab. Or, I could add a club as a winner of the FA Cup in 1904 on the competition's historical winners, but not within the club's own history section.

Does this cause problems when data in one place is missing in the other (nb. missing, not contradicting), or does the game just make an assumption that if A=x, then B must also equal x?