"I've considered becoming black. What if you just changed your racial categorization on all goobermintal forms and such? How could they prove you weren't 1/128th or some such?" I tried that when I moved to Alabama and tried to get a drivers license. The clerk looked into my blue eyes and said "you're not black" and changed the racial designation required on the drivers license.
You should have taken them to court; we need a test case on this.