unbeliever,
It is heartwarming to see you stand up for your sister, and I agree with RunningMan, the only way to stop the whole concept is to stop playing the game. It's sad, but I see it expressed on the board, that people that are the innocent parties feel in the middle because a JW refuses to go to a function with somebody DF'd. If the JW refuses to go, that is their choice, but THEY are the ones who should suffer the loss of the function, not the DF'd one. They are making the choice. When they make the choice, they should be willing to suffer the consequences of their decision. When they impose this decision on others in the family, and they are not willing to accept the loss of the family function or the rift that ensues, then that is emotional blackmail.
I told him that we were not doing her dirty but at worse we were incredibily insensitive for not realizing how she felt. We were totally oblivious to this until her husband pointed it out to us. We canceled the dinner because we felt like shit and we went to her house and had dinner there. The subject was never brought up.
I am a believer in repairing damage whether intentional or not. Bring the subject up to your sister. Apologize for causing hurt even though it wasn't intentional. It can go a long way in healing hurt feelings. I am sure that she will understand and will feel loved by your willingness to repair the hurt. She will also feel loved for your position with your mother.
When I was a dub I refused to go to 2 of my nephews weddings because I was a MS. One of my nephews was baptized but inactive, the other one was never baptized. It caused a great deal of hurt when I did not go. Even though my intention was not to hurt I crushed both of them. When I left the Org I decided to address the issue up front and apologized for my decision and expressed regret that I did not attend the weddings. We now are very close again, and the interesting thing is, they both blamed the Org (even though ultimately I made the choice) and forgave me because they understood the pressure that I was under. Heartfelt apologies and forgiveness are some of the greatest gifts we can give to one another. Regards.
exjdub