More on Allow Multiple Relationships

At the moment turning off Allow Multiple Relationships will only cause the 'create new relationship' hyperlink to disappear from the user profile. However, it is still possible to create more than one relationships using example.com/relationship/$user/create menu.

I think it should work in a way, that a) existing relationships is removed and replaced with new one or b) example.com/relationship/$user/create menu returns "You can't create more than one relationship" (or something like that).

Also, I think it would be much more convenient if this option would be moved to Permissions section for per role settings. What do you think?

Thanks.
B.