"Use another contact's address" creates duplicate relationships

When editing a contact and selecting "Use another contact's address", Core/BAO/Address.php calls the function "createCurrentEmployerRelationship()".  This causes some odd behavior.  In particular, if the relationship already exists, but is not the "primary employer" relationship, then a duplicate relationship with the same contact is created.  

This is certainly not desired behavior in our case, and I suspect in others.  At the very least it ought to be configurable; sharing an address with an organization contact shouldn't automatically force that contact to be the primary employer.

(As an example, think of an individual who is a board member at one organization but is employed by another.  It should be possible for them to get their mail at the organization where they're on the board, without having to make that organization their primary employer.)