ATJ,
I think I remember reading somewhere on JWN that you are still an elder, so I take it that your post is up to date with WT procedures.
I think forging a S-77 and sending in a few phony df'n cards to the society will not cause that much of a disruption for the bro df'd but will cost the WT a few thousand dollars to revamp their system for security breaches which is a very good thing.
If a person can get a good picture of the both sides of the S-77 and envelope and make a good color match they will create quite a stir among the already paraniod GB&Nethanim , and put a little chink in their armor of deniability if summoned before a court to produce records of DF'n and help lay them more vunerable for future charges of corporate responsibility.