Whenever both players have the same support card active on the board, it is impossible to know who owns which.
A frequent case is Nissa’s Pilgrimage since everybody plays with it. When there’s 2 of them on the board, I would like to know which one I own. Anyway, the use cases are many and there is little need for demonstration.
I don’t really care much about the exact method clicking on the gem ties either player to it, maybe reusing the “glow” animation used when you click on an actionable gem