I think I have the perfect answer for that one:
If an elder, or anyone pushes you to sign the card and give them a sample, ask them to read the 8th statement:
STATEMENT OF WITNESSES: The person who signed this document did so in my presence. He or she appears to be of sound mind and free from duress, fraud or undue influence. I am 18 years of age or older.
Then say: According to that statement, you should hand me that piece of paper and let me do what ever I please with it, never suggesting further actions on my part. I know you want that statement to be truthful and not a lie, or a half truth, so, I expect your full collaboration to leave the matter with me and not pressure me in any way.
If for some reason this derails all the way through to your disfellowshipping (which would actually surprise me), than you have an amazing legal case on your hands. Especially if you record every communication you have with them.