I’m not disagreeing with you, but I’m wondering if there have been cases in the past where central banks have broken fungibility based on region or bank assets.

I’m not disagreeing with you, but I’m wondering if there have been cases in the past where central banks have broken fungibility based on region or bank assets. The thing that immediately comes to mind are those “HAWAII” federal reserve notes in WWII which were meant to become worthless should Japan have invaded successfully. That never came to pass, but I’m wondering if that historical event is similar to the kind of thing you are talking about?