That is very interesting.
I actually tried to have that done after I disassociated myself. I was having an awful time with the shunning thing and I tried to get the WTBTS to nullify my baptism -- because I was just a kid and did it intentionally with the thought of pleasing my parents - nothing more nothing less.
Hence if my baptism was nullified - I would not be considered a real JW - hence the DA was redundant - and my status would just be that of a non-Witness (worldly) person. No shunning required.
I never heard back from my letter.