So either I am ultra stupid and weird or this is an issue.
For android if you have the green button for G+ your village should be linked, there isn't anything for iOS.
How about there is a green/red dot next to your IGN or somewhere else on the screen that let's you know that you are linked. If you aren't maybe make it a red and slightly bigger "!" and when a user clicks it they either get told about linking or they get told they are linked.
